Free piston Stirling generator with high power linear motor cooling structure

Abstract

The present invention provides a free piston Stirling generator configured with a high-power linear motor cooling structure, comprising a housing, a linear motor and a first flow guide structure; the linear motor comprises a mover and a stator assembly, a first air gap channel is formed between the mover and the stator assembly, and a second air gap channel is formed between the stator assembly and the housing; one end of the first flow guide structure is connected to the stator assembly, and the other end extends toward the housing, a third air gap channel is formed between the first flow guide structure and the housing, the third air gap channel is connected to the second air gap channel, and the air gap width of the first air gap channel and the air gap width of the third air gap channel are respectively smaller than the air gap width of the second air gap channel. By setting the first flow guide structure, the present invention can make full use of the alternating flow characteristics and time-averaged DC effect of the gas working medium, effectively enhance the internal heat exchange of the linear motor, avoid the linear motor from failing due to excessive local temperature rise of the electromagnetic assembly, or even cause a malfunction, and meet the high-power heat dissipation requirements of the linear motor.

Description

Technical Field

[0001] The invention relates to the field of energy and power technology, and in particular to a free piston Stirling generator equipped with a high-power linear motor cooling structure. Background Art

[0002] The free piston Stirling generator is a new type of thermoelectric conversion device with high efficiency and long life. It belongs to the thermoacoustic heat engine in a broad sense and is composed of an engine unit and a linear motor. As the core unit of the free piston Stirling generator to achieve acoustic-electric conversion, the linear motor has a low operating temperature, which is the key to ensure its efficient and safe operation.

[0003] The existing free piston Stirling generator is mainly equipped with a low-power linear motor. By setting a cooling fluid flow channel outside the casing of the generator unit, the heat generated by the linear motor during operation can be taken away. However, as the output power of the linear motor increases, the motor loss also increases accordingly, that is, the heat generation power of the linear motor increases accordingly. In this case, the casing cooling method based solely on the cooling fluid flow channel can no longer meet the high-power heat dissipation requirements of the linear motor. Long-term operation will cause the local temperature in the linear motor to be too high, resulting in permanent magnet demagnetization and even coil burnout and short circuit. In addition, for some specific occasions with poor heat dissipation conditions, the heat exhaust temperature is required to be increased as much as possible. At this time, it is more important to control the working temperature inside the linear motor. Summary of the invention

[0004] The present invention provides a free piston Stirling generator configured with a high-power linear motor cooling structure, which is used to solve the problem that the existing free piston Stirling generator is difficult to meet the high-power heat dissipation requirements of the linear motor.

[0005] The present invention provides a free piston Stirling generator configured with a high-power linear motor cooling structure, comprising: a housing, a linear motor and a first flow guide structure;

[0006] The linear motor and the first flow guide structure are respectively arranged in the housing; the linear motor comprises a mover and a stator assembly, the mover is movably arranged in the stator assembly, a first air gap channel is formed between the mover and the stator assembly, and a second air gap channel is formed between the stator assembly and the housing;

[0007] One end of the first flow guide structure is connected to the stator assembly, and the other end extends toward the casing to form a third air gap channel between the first flow guide structure and the casing, and the third air gap channel is connected to the second air gap channel, and the air gap width of the first air gap channel and the air gap width of the third air gap channel are respectively smaller than the air gap width of the second air gap channel.

[0008] According to a free piston Stirling generator equipped with a high-power linear motor cooling structure provided by the present invention, a gas working medium is provided in the working environment of the linear motor, and under the action of the power piston, the gas working medium can reciprocate along the first air gap channel, and reciprocate along the connecting flow channel composed of the second air gap channel and the third air gap channel;

[0009] The flow resistance of the gas working medium flowing through the connecting flow channel is of the same magnitude as the flow resistance of the gas working medium flowing through the first air gap channel.

[0010] According to a free-piston Stirling generator equipped with a high-power linear motor cooling structure provided by the present invention, in the working environment of the linear motor, the first air gap channel and the connecting flow channel are connected to form an annular passage; during the reciprocating flow of the gas working medium along the first air gap channel and the connecting flow channel, at least part of the gas working medium flows along the annular passage in the form of time-averaged direct current.

[0011] According to a free piston Stirling generator equipped with a high-power linear motor cooling structure provided by the present invention, the first flow guide structure extends in a ring shape relative to the central axis of the linear motor, and the first flow guide structure is arranged on a side of the linear motor away from the engine unit of the free piston Stirling generator.

[0012] According to a free piston Stirling generator equipped with a high-power linear motor cooling structure provided by the present invention, the first flow guide structure includes a fixing portion and a guiding portion;

[0013] The fixing portion is connected to the stator assembly, the guiding portion is connected to the fixing portion, and the third air gap channel is formed between the guiding portion and the housing.

[0014] According to a free piston Stirling generator equipped with a high-power linear motor cooling structure provided by the present invention, the guide portion includes a first guide section and a second guide section;

[0015] The fixing portion is connected to the first end of the first guide segment, and the second end of the first guide segment is connected to one end of the second guide segment;

[0016] The air gap width between the first end of the first guide section and the housing is greater than the air gap width between the second end of the first guide section and the housing, and the air gap width between the second end of the first guide section and the housing is equal to the air gap width between the second guide section and the housing.

[0017] A free piston Stirling generator configured with a high-power linear motor cooling structure according to the present invention further includes: a second flow guide structure;

[0018] The second flow guide structure extends in a ring shape relative to the central axis of the linear motor, and the second flow guide structure is arranged on a side of the linear motor close to the engine unit and is arranged between the stator assembly and the housing;

[0019] The second flow-guiding structure is provided with a first port, a second port and a gas flow channel connecting the first port and the second port, the second air gap channel is connected with the gas flow channel through the first port, and the first port and the second port have different calibers.

[0020] According to a free piston Stirling generator equipped with a high-power linear motor cooling structure provided by the present invention, there are multiple gas flow channels, and the multiple gas flow channels are arranged in a circle relative to the central axis of the linear motor; or, the gas flow channels extend in a ring shape relative to the central axis of the linear motor.

[0021] A free piston Stirling generator configured with a high-power linear motor cooling structure according to the present invention further includes: a second flow guide structure;

[0022] The second flow guide structure extends in a ring shape relative to the central axis of the linear motor, and the second flow guide structure is arranged on a side of the linear motor close to the engine unit and is arranged between the stator assembly and the housing;

[0023] The second flow-guiding structure is provided with a one-way valve; under the control of the one-way valve, the gas working medium in the working environment of the linear motor flows sequentially through the third air gap channel, the second air gap channel and the one-way valve, and the one-way conduction characteristics of the one-way valve are utilized to increase the time-averaged direct flow rate flowing through the first air gap channel to enhance heat exchange.

[0024] According to a free piston Stirling generator equipped with a high-power linear motor cooling structure provided by the present invention, a plurality of one-way valves are provided, and the plurality of one-way valves are arranged in a circle relative to the central axis of the linear motor.

[0025] A free piston Stirling generator configured with a high-power linear motor cooling structure provided according to the present invention also includes: a cooling fluid flow channel; the cooling fluid flow channel is arranged on the outer wall surface of the casing, and at least part of the cooling fluid flow channel is arranged along the extension direction of the second air gap channel and the third air gap.

[0026] The present invention provides a free piston Stirling generator configured with a high-power linear motor cooling structure. By reasonably designing the first guide structure, the resistance of the gas working medium flowing through the second air gap channel and the third air gap channel in the working environment of the linear motor is close to the resistance of flowing through the first air gap channel. The alternating flow characteristics and time-averaged DC effect of the gas working medium can be fully utilized to effectively enhance the internal heat exchange of the linear motor, avoid the linear motor from failing due to excessive local temperature rise of its electromagnetic components, and even cause malfunctions, thereby meeting the high-power heat dissipation requirements of the linear motor.

[0027] At the same time, the heat dissipation design of the present invention for linear motors can be widely used in the field of high-power thermoacoustic heat engines, and is suitable for the fields of generators and compressors. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 It is a schematic diagram of the structure of a free piston Stirling generator in the prior art;

[0030] Figure 2 It is one of the structural schematic diagrams for cooling the linear motor in the free piston Stirling generator in the prior art;

[0031] Figure 3 This is the second structural schematic diagram of cooling the linear motor in the free piston Stirling generator in the prior art;

[0032] Figure 4 This is one of the structural schematic diagrams of the free piston Stirling generator provided by the present invention and equipped with a high-power linear motor cooling structure;

[0033] Figure 5 This is the second structural schematic diagram of the free piston Stirling generator provided by the present invention and equipped with a high-power linear motor cooling structure;

[0034] Figure 6 This is the third structural schematic diagram of the free piston Stirling generator equipped with a high-power linear motor cooling structure provided by the present invention.

[0035] Reference numerals:

[0036] 10, housing; 101, expansion chamber; 102, compression chamber; 103, back chamber; 111, first air gap channel; 112, second air gap channel; 113, third air gap channel;

[0037] 20. Engine unit; 201. High temperature heat exchanger; 202. Regenerator; 203. Low temperature heat exchanger; 204. Expeller;

[0038] 30. Linear motor; 301. Mover; 302. Stator assembly; 3021. Inner stator; 3022. Outer stator;

[0039] 40. first flow guide structure; 401. fixing portion; 402. guide portion; 4021. first guide section; 4022. second guide section;

[0040] 50. A second flow guiding structure; 501. A gas flow channel;

[0041] 60. Power piston; 70. Cylinder body; 80. Cooling fluid flow channel; 90. Fin heat exchanger. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] like Figure 1 As shown, the free-piston Stirling generator includes a motor unit 20 and a linear motor 30 disposed in a housing 10, and the motor unit 20 and the linear motor 30 are coupled via a resonance unit.

[0044] The engine unit 20 includes a high-temperature heat exchanger 201, a regenerator 202, a low-temperature heat exchanger 203 and an ejector 204. The high-temperature heat exchanger 201, the regenerator 202 and the low-temperature heat exchanger 203 are connected in sequence and arranged coaxially with the ejector 204 as the central axis. The piston of the ejector 204 is supported by a gas spring to ensure the coaxiality of the piston of the ejector 204 and the piston cylinder of the ejector 204. The high-temperature heat exchanger 201 is connected to the inlet end of the ejector 204 through the expansion chamber 101, and the outlet end of the ejector 204, the resonance unit and the end of the low-temperature heat exchanger 203 away from the regenerator 202 are connected through the compression chamber 102. The resonance unit and the inner wall of the housing 10 form a back cavity 103, and the linear motor 30 is arranged in the back cavity 103. The expansion chamber 101 , the compression chamber 102 and the back chamber 103 are all provided with a gas working medium, and the gas working medium may be nitrogen, argon, helium or other inert gases.

[0045] The resonance unit includes a cylinder body 70 and a power piston 60 , a compression chamber 102 is formed between the outlet end of the displacer 204 and the first end of the power piston 60 , and a back chamber 103 is formed between the second end of the power piston 60 , the outer wall of the cylinder body 70 and the inner wall of the casing 10 .

[0046] The linear motor 30 includes a mover 301 and a stator assembly 302. The stator assembly 302 includes an inner stator 3021 and an outer stator 3022. The mover 301 is movably arranged in a gap between the inner stator 3021 and the outer stator 3022. The mover 301 is connected to the power piston 60. The mover 301 includes a plurality of annular permanent magnets, which are connected in sequence along the axial direction of the resonance unit.

[0047] In this way, the power piston 60 reciprocates relative to the cylinder body 70 based on the air pressure difference between the compression chamber 102 and the back chamber 103. During the reciprocating movement of the power piston 60, the power piston 60 drives the mover 301 of the linear motor 30 to reciprocate relative to the stator assembly 302 to convert the mechanical energy of the power piston 60 into electrical energy.

[0048] In actual operation, the engine unit 20 converts thermal energy into the acoustic energy of the compressible fluid in reciprocating oscillation through the thermoacoustic effect, so as to drive the power piston 60 to reciprocate relative to the cylinder body 70, so that the linear motor 30 outputs electrical energy driven by the power piston 60. The remaining acoustic energy will be converted into thermal energy in the form of iron loss, copper loss and damping loss, causing the temperature inside the linear motor 30 to gradually rise.

[0049] Since the mover 301 of the linear motor 30 is usually made of permanent magnets, the permanent magnets will be irreversibly demagnetized after exceeding a certain temperature, which affects the performance of the linear motor 30. At the same time, a coil is arranged in the stator assembly 302 of the linear motor 30, and the insulation layer of the coil also has a certain temperature resistance limit. Excessive temperature can easily cause the insulation layer of the coil to melt, resulting in a short circuit in the stator winding of the linear motor 30. Therefore, a lower operating temperature is the key to ensuring the efficient and safe operation of the linear motor 30, and how to achieve effective heat exchange of the linear motor 30 is one of the problems that must be solved when designing a free piston Stirling generator.

[0050] In order to achieve heat dissipation of the linear motor 30 , the following two methods are generally used to dissipate heat for the linear motor 30 .

[0051] like Figure 2 As shown, in the first heat dissipation solution, a cooling fluid channel 80 corresponding to the back cavity 103 is set outside the housing 10, and the heat generated by the linear motor 30 during operation can be removed by the cooling fluid flowing through the cooling fluid channel 80 through a partition heat exchange method.

[0052] like Figure 3 As shown, in the second heat dissipation scheme, a cooling fluid flow channel 80 corresponding to the back cavity 103 is set outside the casing 10, and a fin heat exchanger 90 is also set in the back cavity 103 of the casing 10. The position of the fin heat exchanger 90 corresponds to the position of the cooling fluid flow channel 80, thereby increasing the heat exchange area between the gas working medium in the back cavity 103 and the external cooling fluid, thereby improving the heat dissipation effect of the linear motor 30.

[0053] The above two heat dissipation solutions mainly rely on the reciprocating oscillation of the gas medium in the back cavity 103 under the action of the power piston 60 to exchange heat. When the output power of the linear motor 30 is relatively small, the above solutions can meet the heat dissipation requirements of the linear motor 30.

[0054] However, as the output power of the linear motor 30 gradually increases, the loss of the linear motor 30 gradually increases, that is, the heat generation power of the linear motor 30 will increase accordingly. In high-power linear motors (above 10kW), as the amount of permanent magnets increases, the proportion of the heat generated by the permanent magnets in the total heat generated by the linear motor 30 increases significantly. Therefore, it is particularly important to enhance the internal heat dissipation of the linear motor 30 and ensure the electromagnetic part of the linear motor 30, especially the permanent magnet, to maintain the operating temperature.

[0055] In practical applications, due to the requirements for the outlet setting of the stator winding, the gap between the outer stator and the casing of the linear motor is usually larger than the gap between the mover (permanent magnet) and the inner and outer stators (about 1 mm). Most of the gas working fluid mainly flows and exchanges heat in the gap between the outer stator and the casing. The permanent magnet is the main heat source in the high-power linear motor, and the temperature rise near it is the most serious. However, the gap near it is relatively large due to the relatively large flow resistance, resulting in poor heat exchange effect. Long-term operation can easily cause permanent magnet demagnetization, and even cause stator windings to burn out and short-circuit. Therefore, the existing heat dissipation solution of linear motors can no longer meet the heat dissipation requirements of high-power linear motors. In addition, for some specific occasions with poor heat dissipation conditions, the heat removal temperature is required to be increased as much as possible. In this scenario, the risk of demagnetization of the permanent magnet is greater (the allowable temperature rise is smaller), so higher requirements are placed on the control of the internal working temperature of the linear motor.

[0056] To solve the above problems, the following Figure 4-Figure 6 A free piston Stirling generator of the present invention is described with a high power linear motor cooling structure.

[0057] like Figures 4 to 6 As shown, the free piston Stirling generator of this embodiment includes: a housing 10 , a linear motor 30 and a first flow guide structure 40 .

[0058] The linear motor 30 and the first flow guide structure 40 are respectively arranged in the housing 10; the linear motor 30 includes a mover 301 and a stator assembly 302, the mover 301 is movably arranged in the stator assembly 302, a first air gap channel 111 is formed between the mover 301 and the stator assembly 302, and a second air gap channel 112 is formed between the stator assembly 302 and the housing 10.

[0059] It can be understood that since the stator assembly 302 includes an inner stator 3021 and an outer stator 3022, the inner stator 3021 is sleeved on the outer side of the cylinder body 70 of the resonance unit, and the outer stator 3022 is sleeved on the outer side of the inner stator 3021, the mover 301 is movably arranged in the first gap between the inner stator 3021 and the outer stator 3022, and the first air gap channel 111 includes a first unit channel and a second unit channel, the first unit channel is arranged between the outer side surface of the inner stator 3021 and the inner side surface of the mover 301, and the second unit channel is arranged between the outer side surface of the mover 301 and the inner side surface of the outer stator 3022.

[0060] At the same time, since the outer stator 3022 is usually provided with a coil winding, according to the requirements for the coil output line setting, a second gap is set between the outer side wall of the outer stator 3022 and the inner wall surface of the housing 10, so that the gap width of the second gap is greater than the gap width of the first gap. Accordingly, the second gap serves as the second air gap channel 112 shown in this embodiment.

[0061] Furthermore, one end of the first flow guide structure 40 of the present embodiment is connected to the stator assembly 302, and the other end extends toward the housing 10, so as to form a third air gap channel 113 between the first flow guide structure 40 and the housing 10, the third air gap channel 113 is connected to the second air gap channel 112, and the air gap width of the first air gap channel 111 and the air gap width of the third air gap channel 113 are respectively smaller than the air gap width of the second air gap channel 112. The first flow guide structure 40 can be arranged on the side of the stator assembly 302 away from the engine unit 20, or on the side of the stator assembly 302 close to the engine unit 20, which is not specifically limited, but it should be noted that the cooling effect is better when it is arranged on the side of the stator assembly 302 away from the engine unit 20.

[0062] It is understandable that, in the process of the power piston 60 reciprocating relative to the cylinder body 70 based on the air pressure difference between the compression chamber 102 and the back chamber 103, the power piston 60 reciprocatingly compresses and expands the back chamber 103, which makes the gas working medium in the working environment of the linear motor 30 have significant alternating flow characteristics. That is, the gas working medium in the working environment of the linear motor 30 can reciprocate along the first air gap channel 111, and reciprocate along the connecting flow channel composed of the second air gap channel 112 and the third air gap channel 113.

[0063] In this embodiment, the air gap width of the third air gap channel 113 can be set according to actual needs, so that under the action of the power piston 60, the magnitude of the flow resistance of the gas working medium flowing through the connecting flow channel is equivalent to the magnitude of the flow resistance of the gas working medium flowing through the first air gap channel 111, that is, the flow resistance of the gas working medium flowing through the connecting flow channel and the flow resistance of the gas working medium flowing through the first air gap channel 111 are at the same magnitude or close in magnitude.

[0064] Of course, based on the above-mentioned arrangement, this embodiment can also make it possible that, under the action of the power piston 60, the difference between the flow resistance of the gas working medium flowing through the connecting flow channel and the flow resistance of the gas working medium flowing through the first air gap channel 111 is less than a preset value. For example, the flow resistance of the gas working medium flowing through the connecting flow channel is close to the flow resistance of the gas working medium flowing through the first air gap channel 111, which makes the flow resistance of the gas working medium flowing through the gap between the outer stator 3022 and the housing 10 close to the flow resistance of the gas working medium flowing through the gap between the permanent magnet and the inner stator 3021 and the outer stator 3022.

[0065] So, compared to Figure 2 and Figure 3 In the design scheme shown, during the process of reciprocating compression and expansion of the back cavity 103 by the power piston 60, more gas working fluid will flow through the gap near the mover 301 (permanent magnet) in the back cavity 103 of this embodiment, and take away the heat from the surface of the permanent magnet by convection heat dissipation, thereby preventing the permanent magnet from demagnetizing due to excessive temperature rise.

[0066] At the same time, in this embodiment, the air gap width of the third air gap channel 113 is set to be smaller than the air gap width of the second air gap channel 112, which can block the gap between the outer stator 3022 and the casing 10 to a certain extent. In the process of reciprocating compression and expansion of the back cavity 103 by the power piston 60, it is beneficial to increase the oscillating mass flow in the back cavity 103 and enhance the convective heat exchange between the gas working fluid and the permanent magnet, the stator assembly 302 and the casing 10.

[0067] In addition, in the working environment of the linear motor 30, the first air gap channel 111 and the connecting flow channel are connected to form an annular passage. Since the first air gap channel 111 includes the first unit channel and the second unit channel, a topological loop can be formed between the above-mentioned connecting flow channel, the first unit channel and the second unit channel. Since the connecting flow channel, the first unit channel and the second unit channel are all extended in a ring shape relative to the central axis of the linear motor 30, the connecting flow channel is an irregular structure, and the gap width of the first unit channel and the gap width of the second unit channel are respectively different from the gap width of the connecting flow channel, the connecting flow channel, the first unit channel and the second unit channel have a certain asymmetry in structure. Therefore, in the process of the gas working medium reciprocating along the first air gap channel 111 and the connecting flow channel, at least part of the gas working medium flows along the annular passage in the form of time-averaged direct current. Among them, the above-mentioned time-averaged direct current can flow through the connecting flow channel, the first unit channel and the second unit channel respectively, and these time-averaged direct currents also play a part in enhancing heat exchange.

[0068] It can be seen from the above that this embodiment reasonably designs the first flow guide structure 40 so that the resistance of the gas working medium flowing through the second air gap channel 112 and the third air gap channel 113 in the working environment of the linear motor 30 is close to the resistance of flowing through the first air gap channel 111. The alternating flow characteristics and time-averaged DC effect of the gas working medium in the back cavity 103 can be fully utilized to effectively enhance the internal heat exchange of the linear motor 30, avoid the linear motor 30 from failing due to excessive local temperature rise of its electromagnetic components, or even cause malfunctions, thereby meeting the high-power heat dissipation requirements of the linear motor 30.

[0069] At the same time, the heat dissipation design for the linear motor 30 in this embodiment can be widely used in the field of high-power thermoacoustic heat engines, and is suitable for the fields of generators and compressors.

[0070] In some embodiments, Figure 4 As shown, in the process of reciprocating compression and expansion of the back cavity 103 by the power piston 60, in order to ensure that more gas working fluid flows through the gap between the mover 301 and the inner stator 3021 and the outer stator 3022, the first flow guide structure 40 is arranged in a ring shape relative to the central axis of the linear motor 30 in this embodiment, and the first flow guide structure 40 is arranged on the side of the linear motor 30 away from the engine unit 20 of the free piston Stirling generator.

[0071] Specifically, the first air guide structure 40 of the present embodiment includes a fixing portion 401 and a guiding portion 402; the fixing portion 401 is connected to one end of the stator assembly 302 away from the engine unit 20, the guiding portion 402 is connected to the fixing portion 401, and a third air gap channel 113 is formed between the guiding portion 402 and the housing 10. The fixing portion 401 and the guiding portion 402 are both plate-shaped, and both the fixing portion 401 and the guiding portion 402 extend in a ring shape relative to the central axis of the linear motor 30.

[0072] Since the casing 10 of the free piston Stirling generator is usually columnar, for example, a part of the casing 10 corresponding to the back cavity 103 is cylindrical, the present embodiment is based on the setting of the first guide structure 40, so that the guide part 402 can be set close to the inner wall surface of the casing 10 and extend along the extension direction of the inner wall surface of the casing 10, so as to form a third air gap channel 113 between the guide part 402 and the casing 10, and the gap width of the third air gap channel 113 can be set according to actual needs.

[0073] In some embodiments, Figure 5 As shown, the guide portion 402 of this embodiment includes a first guide segment 4021 and a second guide segment 4022; the fixing portion 401 is fixed to one end of the outer stator 3022 facing away from the engine unit 20, the fixing portion 401 is connected to the first end of the first guide segment 4021, and the second end of the first guide segment 4021 is connected to one end of the second guide segment 4022.

[0074] Among them, the air gap width between the first end of the first guide section 4021 and the casing 10 is equal to the air gap width between the outer side surface of the outer stator 3022 and the inner wall surface of the casing 10, the air gap width between the first end of the first guide section 4021 and the casing 10 is greater than the air gap width between the second end of the first guide section 4021 and the casing 10, and the air gap width between the second end of the first guide section 4021 and the casing 10 is equal to the air gap width between the second guide section 4022 and the casing 10.

[0075] In this way, when the guide portion 402 is plate-shaped and extends in a ring shape relative to the central axis of the linear motor 30, a flow channel with a uniform gap can be formed between the second guide section 4022 and the housing 10, and a tapered variable diameter flow channel can be formed between the first guide section 4021 and the housing 10, thereby intensifying the asymmetry of the flow channel structure between the connecting flow channel composed of the second air gap channel 112 and the third air gap channel 113 and the first air gap channel 111, thereby increasing the time-averaged DC flow rate of the gas working fluid and ultimately enhancing the heat dissipation effect on the linear motor 30.

[0076] It should be pointed out here that since the influence of the flow channel structure on the direct current is relatively complex, the design parameters of the first guide section 4021 and the second guide section 4022 can be determined by simulation according to actual needs.

[0077] Based on the scheme shown in the above embodiment, Figure 6 As shown, in order to enhance the heat dissipation effect of the linear motor 30 , a second flow guide structure 50 is further provided in this embodiment.

[0078] The second flow guiding structure 50 extends in a ring shape relative to the central axis of the linear motor 30, and is disposed on a side of the linear motor 30 close to the engine unit 20, and is disposed between the stator assembly 302 and the housing 10. For example, in this embodiment, the second flow guiding structure 50 is disposed between one end of the outer stator 3022 close to the engine unit 20 and the inner wall surface of the housing 10.

[0079] The second flow guiding structure 50 is provided with a first port, a second port and a gas flow channel 501 connecting the first port and the second port. The second air gap channel 112 is connected with the gas flow channel 501 through the first port. The caliber of the first port is different from the caliber of the second port.

[0080] In one example, the gas flow channel 501 of this embodiment is distributed along the radial direction of the linear motor 30 , and the inner diameter of the gas flow channel 501 gradually increases in the extending direction from the first port to the second port.

[0081] In this way, on the basis of setting the first guide structure 40 for the linear motor 30, by further setting the second guide structure 50, the asymmetry of the connecting flow channel composed of the second air gap channel 112 and the third air gap channel 113 and the first air gap channel 111 in the flow channel structure can be further intensified, thereby increasing the time-averaged DC flow rate of the gas working fluid in each loop and improving the heat dissipation effect of the linear motor 30.

[0082] Furthermore, in this embodiment, according to actual needs, multiple gas flow channels 501 can be provided, and the multiple gas flow channels 501 are arranged circumferentially relative to the central axis of the linear motor 30. For example, in this embodiment, the multiple gas flow channels 501 can be evenly distributed circumferentially relative to the central axis of the linear motor 30.

[0083] Of course, in this embodiment, the gas flow channel 501 can also be extended in a ring shape relative to the central axis of the linear motor 30. That is, the gas flow channel 501 is an annular flow channel coaxially arranged with the linear motor 30, and the diameter of the first port of the gas flow channel 501 is smaller than the diameter of the second port of the gas flow channel 501.

[0084] Based on the scheme shown in the above embodiment, in order to enhance the heat dissipation effect of the linear motor 30, the present embodiment can also replace the gas flow channel 501 of the above embodiment with a one-way valve, so as to increase the time-averaged DC flow rate of the gas working medium during the reciprocating oscillation process based on the setting of the one-way valve and utilize the one-way conduction characteristics of the one-way valve, thereby enhancing the heat dissipation effect of the linear motor 30.

[0085] Specifically, under the control of the one-way valve, the gaseous medium in the working environment of the linear motor 30 flows sequentially through the third air gap channel 113, the second air gap channel 112 and the one-way valve. Multiple one-way valves can be provided, and the multiple one-way valves are arranged circumferentially relative to the central axis of the linear motor 30.

[0086] It should be pointed out here that in order to control the time-averaged direct flow rate of the gas working medium flowing through the connecting flow channel composed of the second air gap channel 112 and the third air gap channel 113, as well as the first unit channel and the second unit channel, the present embodiment can optimize the caliber of the above-mentioned first port and the second port to achieve a better and more controllable heat dissipation effect for the linear motor 30.

[0087] Based on the solution of the above embodiment, this embodiment can also set a cooling fluid flow channel 80 on the outer wall of the housing 10, and at least part of the cooling fluid flow channel 80 is set along the extension direction of the second air gap channel 112 and the third air gap. In this way, this embodiment can also remove the heat generated by the linear motor 30 when it is working through the cooling fluid flowing through the cooling fluid flow channel 80.

[0088] Of course, if the layout conditions permit, the present embodiment may also set a fin heat exchanger in the back cavity, and the position of the fin heat exchanger is opposite to the position of the cooling fluid flow channel, so as to further enhance the heat dissipation effect of the linear motor based on the set fin heat exchanger.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A free piston Stirling generator equipped with a high-power linear motor cooling structure, characterized in that: include: A housing, a linear motor and a first flow guide structure; The linear motor and the first flow guide structure are respectively arranged in the housing; the linear motor comprises a mover and a stator assembly, the mover is movably arranged in the stator assembly, a first air gap channel is formed between the mover and the stator assembly, and a second air gap channel is formed between the stator assembly and the housing; One end of the first flow guide structure is connected to the stator assembly, and the other end extends toward the housing to form a third air gap channel between the first flow guide structure and the housing, the third air gap channel is connected to the second air gap channel, and the air gap width of the first air gap channel and the air gap width of the third air gap channel are respectively smaller than the air gap width of the second air gap channel; The first flow guiding structure extends in a ring shape relative to the central axis of the linear motor, and the first flow guiding structure is arranged on a side of the linear motor away from the engine unit of the free piston Stirling generator; The first flow guiding structure includes a fixing portion and a guiding portion; The fixing portion is connected to the stator assembly, the guiding portion is connected to the fixing portion, and the third air gap channel is formed between the guiding portion and the housing.

2. The free piston Stirling generator with a high-power linear motor cooling structure according to claim 1, characterized in that: A gas working medium is provided in the working environment of the linear motor. Under the action of the power piston, the gas working medium can flow back and forth along the first air gap channel, and can flow back and forth along the connecting flow channel formed by the second air gap channel and the third air gap channel; The flow resistance of the gas working medium flowing through the connecting flow channel is of the same magnitude as the flow resistance of the gas working medium flowing through the first air gap channel.

3. The free piston Stirling generator with a high-power linear motor cooling structure according to claim 2, characterized in that: In the working environment of the linear motor, the first air gap channel and the connecting flow channel are connected to form an annular passage; during the reciprocating flow of the gas working medium along the first air gap channel and the connecting flow channel, at least part of the gas working medium flows along the annular passage in the form of time-averaged direct current.

4. The free piston Stirling generator with a high-power linear motor cooling structure according to claim 1, characterized in that: The guide portion includes a first guide section and a second guide section; The fixing portion is connected to the first end of the first guide segment, and the second end of the first guide segment is connected to one end of the second guide segment; The air gap width between the first end of the first guide section and the housing is greater than the air gap width between the second end of the first guide section and the housing, and the air gap width between the second end of the first guide section and the housing is equal to the air gap width between the second guide section and the housing.

5. The free piston Stirling generator with a high-power linear motor cooling structure according to claim 1, characterized in that: Also includes: a second flow guiding structure; The second flow guide structure extends in a ring shape relative to the central axis of the linear motor, and the second flow guide structure is arranged on a side of the linear motor close to the engine unit and is arranged between the stator assembly and the housing; The second flow-guiding structure is provided with a first port, a second port and a gas flow channel connecting the first port and the second port, the second air gap channel is connected with the gas flow channel through the first port, and the first port and the second port have different calibers.

6. The free piston Stirling generator with a high-power linear motor cooling structure according to claim 5, characterized in that: The gas flow passages are provided in plurality, and the plurality of gas flow passages are arranged in a circle relative to the central axis of the linear motor; Alternatively, the gas flow channel extends in a ring shape relative to the central axis of the linear motor.

7. The free piston Stirling generator with a high-power linear motor cooling structure according to claim 1, characterized in that: Also includes: a second flow guiding structure; The second flow guide structure extends in a ring shape relative to the central axis of the linear motor, and the second flow guide structure is arranged on a side of the linear motor close to the engine unit and is arranged between the stator assembly and the housing; The second flow-guiding structure is provided with a one-way valve; under the control of the one-way valve, the gaseous working medium in the working environment of the linear motor flows through the third air gap channel, the second air gap channel and the one-way valve in sequence.

8. The free piston Stirling generator with a high-power linear motor cooling structure according to any one of claims 1 to 3, characterized in that: Also includes: cooling fluid flow channel; The cooling fluid flow channel is arranged on the outer wall surface of the housing, and at least a part of the cooling fluid flow channel is arranged along the extension direction of the second air gap channel and the third air gap.

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