A variable volume electromagnetic spring Stirling generator for testing

Abstract

A variable volume electromagnetic spring Stirling generator for testing includes an expansion chamber volume control device, a back pressure chamber volume control device, an expansion chamber charging and discharging device, a back pressure chamber charging and discharging device and a controller; a housing includes an expansion chamber housing, an intermediate housing and a back pressure chamber housing; the expansion chamber volume control device controls the expansion chamber housing to move up and down, and the back pressure chamber volume control device controls the back pressure chamber housing to move up and down; the expansion chamber charging and discharging device is connected to the expansion chamber charging valve, the back pressure chamber charging and discharging device is connected to the back pressure chamber charging valve, and the controller is respectively connected to the expansion chamber charging and discharging device, the back pressure chamber charging and discharging device, the expansion chamber volume control device and the back pressure chamber volume control device. The present invention uses the volume control device to control the expansion chamber and the back pressure chamber housing to stretch or contract, and adjust the longitudinal length of the Stirling generator, thereby adapting to the stroke changes of the valve piston and the power piston.

Description

Technical Field

[0001] The invention relates to a Stirling generator, in particular to a variable-capacity electromagnetic spring Stirling generator for testing. Background Art

[0002] As an advanced and efficient external combustion heat-to-work conversion device, the free piston Stirling generator is widely compatible with various existing heat sources. The generator eliminates the complex crankshaft connecting rod mechanism in the traditional Stirling engine, freeing the power piston and the valve piston from the constraints of the mechanical structure and achieving complete independence of movement. As a result, the generator shows significant advantages such as simple structure, high thermoelectric conversion efficiency, low noise and vibration, strong self-starting ability, high reliability and long life. In many fields such as solar energy, geothermal energy, waste heat recovery and deep space exploration, the generator has shown broad application prospects.

[0003] As a new type of free piston Stirling generator, the electromagnetic spring Stirling generator uses an electromagnetic spring to replace the leaf spring assembly in the traditional free piston Stirling generator. The electromagnetic spring includes a linear motor, which generates a rebound force on the piston by providing the linear motor with alternating current in the opposite direction of the piston displacement to simulate the working characteristics of the leaf spring. The fatigue fracture problem of the leaf spring in the traditional Stirling generator is solved. Since the amplitude of the alternating current can be adjusted by the converter, the magnitude of the rebound force can be controlled, which is equivalent to adjusting the stiffness of the leaf spring of the traditional Stirling generator. By applying an appropriate control strategy, the phase difference between the valve piston and the power piston can be adjusted.

[0004] In the experiment of studying the effect of charging pressure on the efficiency of free piston Stirling generator, as the charging pressure increases, in the traditional free piston Stirling generator, the phase difference between the gas piston and the power piston gradually decreases, and at the same time, the stroke of the gas piston and the power piston will also become smaller. When the charging pressure decreases, the opposite is true. The change in the phase difference between the gas piston and the power piston can be solved by adjusting the amplitude of the alternating current on the electromagnetic spring. For the change in the stroke of the gas piston and the power piston, if the stroke is too large, it may cause the gas piston to hit the cylinder; if the stroke is too small, a large dead volume will be generated. These situations will significantly affect the output power of the Stirling generator and cause significant interference to the experiment. In order to ensure that the stroke of the gas piston and the power piston matches the length of the Stirling generator under different air pressures, multiple sets of Stirling generators of different lengths must be designed. This not only increases the cost of the experiment, but also requires reassembly every time the air pressure is changed, which also makes the experimental process time-consuming and laborious. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the above-mentioned background technology and provide a variable volume electromagnetic spring Stirling generator for testing, which uses a volume control device to control the stretching or contraction of the outer shell of the expansion chamber and the back pressure chamber, and adjusts the longitudinal length of the Stirling generator, thereby adapting to the stroke changes of the valve piston and the power piston.

[0006] The technical solution adopted by the present invention to solve its technical problems is a variable volume electromagnetic spring Stirling generator for testing, comprising a Stirling generator body, an expansion chamber volume control device, a back pressure chamber volume control device, an expansion chamber charging and discharging device, a back pressure chamber charging and discharging device and a controller; the Stirling generator body comprises a shell, a cylinder, a gas distribution piston, a power piston and an electromagnetic spring, the electromagnetic spring is connected with the gas distribution piston and the power piston, the shell comprises an expansion chamber shell, an intermediate shell and a back pressure chamber shell, the intermediate shell is a structure with two ends open, the expansion chamber shell is located above the intermediate shell and is sealed with the intermediate shell, the back pressure chamber shell is located below the intermediate shell and is sealed with the intermediate shell; the cylinder is arranged in the intermediate shell, the gas distribution piston and the power piston are arranged in the cylinder from top to bottom in sequence, a connecting rod is arranged at the lower end of the gas distribution piston, the power piston is sleeved in the middle of the connecting rod, the space formed between the gas distribution piston and the expansion chamber shell is the expansion chamber, the space formed between the gas distribution piston and the power piston is the compression chamber, and the space formed between the power piston and the back pressure chamber shell is the back pressure chamber;

[0007] The expansion chamber volume control device is arranged on the expansion chamber shell, and the expansion chamber volume control device can be used to control the expansion chamber shell to move up and down in the axial direction of the intermediate shell. The back pressure chamber volume control device is arranged on the back pressure chamber shell, and the back pressure chamber volume control device can be used to control the back pressure chamber shell to move up and down in the axial direction of the intermediate shell. An expansion chamber inflation valve is provided on the expansion chamber shell, and a back pressure chamber inflation valve is provided on the back pressure chamber shell. The expansion chamber inflation and deflation device is connected to the expansion chamber inflation valve, and the back pressure chamber inflation and deflation device is connected to the back pressure chamber inflation valve. The controller is respectively connected to the expansion chamber inflation and deflation device, the back pressure chamber inflation and deflation device, the expansion chamber volume control device, and the back pressure chamber volume control device.

[0008] Furthermore, a circle of grooves is provided on the side surfaces of the expansion chamber shell and the back pressure chamber shell, and a sealing member is provided in the groove.

[0009] Furthermore, the sealing member comprises a sealing lip, a locking ring and a spring energizer. The locking ring and the spring energizer are arranged in the sealing lip, and the spring energizer is located between the sealing lip and the locking ring.

[0010] Furthermore, an expansion chamber helium tank and a back pressure chamber helium tank are provided. The expansion chamber helium tank is connected to the expansion chamber inflation and deflation device, and the back pressure chamber helium tank is connected to the back pressure chamber inflation and deflation device.

[0011] Furthermore, the power piston and the gas distribution piston are both provided with displacement sensors; and the expansion chamber shell is provided with an impact sensor.

[0012] Furthermore, the Stirling generator body also includes a heater, a regenerator, and a cooler. The heater, the regenerator, and the cooler are arranged from top to bottom between the cylinder and the intermediate shell, and an insulating ring is provided between the heater, the regenerator, the cooler and the intermediate shell.

[0013] Furthermore, the electromagnetic spring includes a first linear motor, a second linear motor, an energy storage device, a current transformer and a frequency converter. The energy storage device is connected to the first linear motor through the current transformer, the first linear motor is connected to the frequency converter, and the frequency converter is connected to the second linear motor; the first linear motor is connected to the power piston, and the second linear motor is connected to the gas distribution piston.

[0014] Further, the first linear motor includes a first linear motor stator and a first linear motor mover, the first linear motor stator is fixed on the intermediate outer shell, and the first linear motor mover is fixed to the lower end of the power piston through a connecting bracket; the second linear motor includes a second linear motor stator and a second linear motor mover, the second linear motor stator is fixed to the intermediate outer shell through a connecting bracket, and the second linear motor mover is sleeved on the lower end of the valve piston connecting rod.

[0015] Furthermore, the first linear motor and the second linear motor are arranged in the back pressure chamber.

[0016] Furthermore, a fixed frame is provided, and the Stirling generator body, the expansion chamber volume control device, and the back pressure chamber volume control device are arranged in the fixed frame, and the expansion chamber volume control device is connected between the fixed frame and the expansion chamber shell, and pushes the expansion chamber shell to control the longitudinal length of the expansion chamber; the back pressure chamber volume control device is connected between the fixed frame and the back pressure chamber shell, and pushes the back pressure chamber shell to control the longitudinal length of the back pressure chamber.

[0017] Compared with the prior art, the advantages of the present invention are as follows:

[0018] The present invention controls the axial up and down movement of the expansion chamber shell in the middle shell through the expansion chamber volume control device to control the longitudinal length of the expansion chamber, and controls the axial up and down movement of the back pressure chamber shell in the middle shell through the back pressure chamber volume control device to control the longitudinal length of the back pressure chamber, so that the longitudinal length of the Stirling generator can be variable, thereby adapting to the stroke changes of the gas distribution piston and the power piston caused by the working air pressure changes. It is convenient to eliminate the influence of the gas distribution piston hitting the cylinder or the excessive dead volume on the experiment in the experiment of testing the influence of the inflation pressure on the efficiency of the free piston Stirling generator, which provides convenience for the experimental operation, reduces the experimental cost, and saves time and labor. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1It is a schematic structural diagram of an embodiment of the present invention.

[0020] Figure 2 yes Figure 1 Schematic diagram of the connection between the expansion chamber housing and the intermediate housing in the illustrated embodiment.

[0021] Figure 3 yes Figure 1 A schematic diagram of the structure of the sealing member inside the expansion chamber housing of the illustrated embodiment.

[0022] Figure 4 yes Figure 1 Schematic diagram of the minimum volume state of the embodiment shown.

[0023] Figure 5 yes Figure 1 Schematic diagram of the maximum volume state of the embodiment shown.

[0024] In the figure, 1 is a heater, 2 is a regenerator, 3 is a cooler, 4 is an insulation ring, 5 is a gas distribution piston, 6 is a power piston, 7 is a cylinder, 8 is an expansion chamber, 9 is a compression chamber, 10 is a back pressure chamber, 11 is a stator of a first linear motor, 12 is a mover of a first linear motor, 13 is a stator of a second linear motor, 14 is a mover of a second linear motor, 15 is a volume control device of an expansion chamber, 16 is a volume control device of a back pressure chamber, 17 is an expansion chamber shell, 18 is a back pressure chamber shell, 19 is an expansion chamber inflation valve, 20 is an back pressure chamber inflation valve, 21 is a fixing frame, 22 is an impact sensor, 23 is a controller, 24 is an expansion chamber helium tank, 25 is an inflation and deflation device of an expansion chamber, 26 is an back pressure chamber helium tank, 27 is an inflation and deflation device of a back pressure chamber, 28 is a seal, 29 is a seal lip, 30 is a locking ring, 31 is a spring energizer, and 32 is an intermediate shell. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] Reference Figure 1 , Figure 2 The variable volume electromagnetic spring Stirling generator used for testing in this embodiment includes a Stirling generator body, an expansion chamber volume control device 15, a back pressure chamber volume control device 16, an expansion chamber charging and discharging device 25, a back pressure chamber charging and discharging device 27, an expansion chamber helium tank 24, a back pressure chamber helium tank 26 and a controller 23.

[0027] The Stirling generator body includes a housing, a cylinder 7, a gas distribution piston 5, a power piston 6 and an electromagnetic spring. The electromagnetic spring is connected to the gas distribution piston 5 and the power piston 6. The housing includes an expansion chamber housing 17, an intermediate housing 32 and a back pressure chamber housing 18. The intermediate housing 32 is a structure with two ends open. The expansion chamber housing 17 is located above the intermediate housing 32 and is sealed and connected to the intermediate housing 32. The back pressure chamber housing 18 is located below the intermediate housing 32 and is sealed and connected to the intermediate housing 32. The cylinder 7 is arranged in the intermediate housing 32. The gas distribution piston 5 and the power piston 6 are arranged in the cylinder 7 from top to bottom. A connecting rod is arranged at the lower end of the gas distribution piston 5. The power piston 6 is sleeved in the middle of the connecting rod. The space formed between the gas distribution piston 5 and the expansion chamber housing 17 is the expansion chamber 8. The space formed between the gas distribution piston 5 and the power piston 6 is the compression chamber 9. The space formed between the power piston 6 and the back pressure chamber housing 18 is the back pressure chamber 10.

[0028] The expansion chamber volume control device 15 is arranged on the expansion chamber housing 17, and the expansion chamber volume control device 15 can control the expansion chamber housing 17 to move up and down in the axial direction of the intermediate housing 32. The back pressure chamber volume control device 16 is arranged on the back pressure chamber housing 18, and the back pressure chamber volume control device 16 can control the back pressure chamber housing 18 to move up and down in the axial direction of the intermediate housing 32. The sides of the expansion chamber housing 17 and the back pressure chamber housing 18 are both provided with a circle of grooves, and a sealing member 28 is provided in the groove to ensure the sealing between the expansion chamber housing 17, the back pressure chamber housing 18 and the intermediate housing 32 to prevent helium leakage. The expansion chamber housing 17 is provided with an expansion chamber inflation valve 19 and an impact sensor 22, and the back pressure chamber housing 18 is provided with a back pressure chamber inflation valve 20.

[0029] Reference Figure 3 The seal 28 includes a sealing lip 29, a locking ring 30, and a spring energizer 31. The locking ring 30 and the spring energizer 31 are arranged in the sealing lip 29, and the spring energizer 31 is located between the sealing lip 29 and the locking ring 30. The sealing lip 29 is made of high-performance polyetheretherketone carbon fiber and polytetrafluoroethylene synthetic materials, which are resistant to high temperature and high pressure and are responsible for contacting with the Stirling generator housing to form a seal. The locking ring 30 is responsible for preventing the seal 28 from rotating in the metal part and promoting consistent sealing contact under thermal cycle conditions. The spring energizer 31 is used to provide elasticity to promote the contact between the sealing lip 29 and the wall of the Stirling generator housing.

[0030] The expansion chamber helium tank 24 is connected to the expansion chamber inflation and deflation device 25, the expansion chamber inflation and deflation device 25 is connected to the expansion chamber inflation valve 19, the back pressure chamber helium tank 26 is connected to the back pressure chamber inflation and deflation device 27, the back pressure chamber inflation and deflation device 27 is connected to the back pressure chamber inflation valve 20, and the controller 23 is respectively connected to the expansion chamber inflation and deflation device 25, the back pressure chamber inflation and deflation device 27, the expansion chamber volume control device 15, and the back pressure chamber volume control device 16.

[0031] The Stirling generator body also includes a heater 1, a regenerator 2, and a cooler 3. The heater 1, the regenerator 2, and the cooler 3 are arranged from top to bottom between the cylinder 7 and the intermediate casing 32. An insulating ring 4 is provided between the heater 1, the regenerator 2, the cooler 3 and the intermediate casing 32 to reduce the heat loss of the expansion chamber 8 and prevent high temperature from affecting the insulation between the expansion chamber 8 and the expansion chamber casing 17.

[0032] The electromagnetic spring includes a first linear motor, a second linear motor, an energy storage device, a current transformer and a frequency converter. The energy storage device is connected to the first linear motor through the current transformer, the first linear motor is connected to the frequency converter, and the frequency converter is connected to the second linear motor. The first linear motor is connected to the power piston 6, and the second linear motor is connected to the gas piston 5. Displacement sensors are provided on the power piston 6 and the gas piston 5.

[0033] The first linear motor includes a first linear motor stator 11 and a first linear motor mover 12. The first linear motor stator 11 is fixed on the intermediate housing 32. The first linear motor mover 12 is fixed to the lower end of the power piston 6 through a connecting bracket. The second linear motor includes a second linear motor stator 13 and a second linear motor mover 14. The second linear motor stator 13 is fixed to the intermediate housing 32 through a connecting bracket. The second linear motor mover 14 is sleeved on the lower end of the gas distribution piston connecting rod. The first linear motor and the second linear motor are arranged in the back pressure chamber 10. By applying a current opposite to the piston displacement direction to the linear motor, a rebound force on the piston is generated, thereby simulating the effect of the leaf spring in the traditional Stirling generator. The amplitude of the applied current can be adjusted by a converter to change the magnitude of the rebound force generated, which is equivalent to changing the stiffness of the leaf spring in the traditional Stirling generator. Through a reasonable control strategy, the phase difference between the gas distribution piston and the power piston can be ensured to remain unchanged.

[0034] A fixed frame 21, a Stirling generator body, and an expansion chamber volume control device 15 are also provided. The back-pressure chamber volume control device 16 is arranged in the fixed frame 21. The expansion chamber volume control device 15 is connected between the fixed frame 21 and the expansion chamber shell 17, and pushes the expansion chamber shell 17 to control the longitudinal length of the expansion chamber 8; the back-pressure chamber volume control device 16 is connected between the fixed frame 21 and the back-pressure chamber shell 18, and pushes the back-pressure chamber shell 18 to control the longitudinal length of the back-pressure chamber 10.

[0035] In this embodiment, the gap between the gas piston 5 and the inner wall of the cylinder 7 is 0.1mm, the gap between the power piston 6 and the inner wall of the cylinder 7 is 0.04mm, and the gap between the power piston 6 and the outer wall of the connecting rod of the gas piston 5 is 0.04mm. During the reciprocating motion, the friction is ensured to be small enough to ensure air tightness.

[0036] In this embodiment, the inner diameter of the expansion chamber 8 is 60 mm, the diameter of the expansion chamber shell 17 is 80 mm, the inner diameter of the compression chamber 9 is 60 mm, the inner diameter of the back pressure chamber 10 is 120 mm, and the diameter of the back pressure chamber shell 18 is approximately equal to the inner diameter of the back pressure chamber 10, i.e., 120 mm. In the minimum volume state of the Stirling generator, the total volume of the expansion chamber 8 and the compression chamber 9 is 84780 mm 3 , the volume of the back pressure chamber 10 is 381500mm 3 .

[0037] Reference Figure 4 , Figure 5 When the Stirling generator is in its minimum volume state, the expansion chamber volume control device 15 can control the expansion chamber shell 17 to expand outward by 12 mm, and the back pressure chamber volume control device 16 can control the back pressure chamber shell 18 to expand outward by 24 mm. In the Stirling generator, the air pressure in the expansion chamber 8 and the compression chamber 9 is maintained at a roughly equal level. According to calculations, during the expansion process, the controller 23 controls the expansion chamber volume control device 15 and the back pressure chamber volume control device 16 to achieve synchronous but opposite movement in the vertical direction according to a strictly set 1:2 ratio, so that the sum of the volumes of the expansion chamber 8 and the compression chamber 9 and the volume of the back pressure chamber 10 increase or decrease year-on-year, thereby causing the average working pressure of the working fluid in the expansion chamber 8 and the back pressure chamber 10 of the Stirling generator to change year-on-year, so as to ensure the stable operation of the Stirling generator during the volume change process.

[0038] The variable volume electromagnetic spring Stirling generator used for testing of the present invention can test the influence of the charging pressure on the efficiency of the electromagnetic spring Stirling generator.

[0039] The controller 23 integrates a single-chip control module, and the built-in program of the single-chip control module stores the amount of helium in the same volume at different temperatures. The controller 23 can manage the inflation and deflation device to perform the following tasks: 1. During the experiment, when the volume of the Stirling generator increases and the average air pressure decreases, and the air pressure needs to be supplemented to the Stirling generator, the controller 23 performs corresponding operations. The controller 23 calculates the amount of helium required to be supplemented according to the increase in the volume of the expansion chamber 8 and the back pressure chamber 10 of the Stirling generator and the initial air pressure at room temperature, and supplements it through the expansion chamber inflation valve 19 and the back pressure chamber inflation valve 20. 2. When an experiment is completed and the pressure needs to be reduced to start the second experiment, the controller 23 calculates the amount of helium required to be released according to the temperature of the expansion chamber 8 and the back pressure chamber 10, the initial air pressure value of the previous experiment, the initial air pressure value of the current experiment, and the volume of the expansion chamber 8 and the compression chamber 9 and the volume of the back pressure chamber 10, and releases it through the expansion chamber inflation valve 19 and the back pressure chamber inflation valve 20.

[0040] When the impact sensor 22 detects a collision signal, the controller 23 can adjust the volume control device to shrink the expansion chamber volume control device 15 and the back pressure chamber volume control device 16 in a ratio of 1:2, so as to provide more space for the gas distribution piston 5, until the impact sensor 22 no longer detects the collision signal. At the same time, the controller 23 records the outward expansion distance of the expansion chamber housing 17 and the back pressure chamber housing 18, and transmits it to the control program of the inflation and deflation device.

[0041] There are two test methods for the experiment on the effect of inflation pressure on the efficiency of free piston Stirling generator: constant hot end temperature and constant heating power.

[0042] In the efficiency test experiment with constant hot end temperature, a set of air pressure gradients is first set, the Stirling generator is adjusted to the minimum volume state, and the highest initial air pressure in the gradient is filled. After the inflation is completed, the heater is started to gradually increase the temperature of the expansion chamber 8 of the Stirling generator. For every 10°C increase in temperature, one cycle of alternating current is applied to the first linear motor to drive the power piston 6 to reciprocate once. Subsequently, based on the signals of the displacement sensors on the power piston 6 and the valve piston 5, the first linear motor and the second linear motor are quickly controlled to provide alternating current in the opposite direction of the piston displacement, thereby generating a rebound force on the piston to simulate the working characteristics of the leaf spring in the traditional Stirling generator. If the Stirling generator runs stably, it means that the minimum starting temperature has been reached; if the Stirling generator fails to start, the minimum starting temperature has not yet been reached. After the temperature of the expansion chamber rises by 10°C, the process is repeated until the Stirling generator is successfully started. After starting, the alternating current in the opposite direction of the piston displacement is maintained, and in the process of continuing to heat up, the amplitude of the alternating current of the two linear motors is controlled in real time by the inverter to ensure that the phase difference between the gas distribution piston 5 and the power piston 6 is slightly less than 90°. During the temperature increase process, the stroke of the gas distribution piston 5 and the power piston 6 will increase until the top of the gas distribution piston 5 touches the impact sensor 22. The impact sensor 22 sends an impact signal to the controller 23, and the controller 23 adjusts the expansion chamber volume control device 15 and the back pressure chamber volume control device 16 to shrink them at a ratio of 1:2 to provide more space for the gas distribution piston until the impact sensor 22 no longer receives the impact signal. At the same time, the controller 23 manages the charging and discharging device to add helium to the inside of the Stirling generator to maintain a constant air pressure. Until the predetermined expansion chamber temperature is reached, after the Stirling generator runs stably, the ratio of the linear motor output power to the heater input power is calculated to complete the efficiency test under the current air pressure.

[0043] After the experiment under the current air pressure is completed, there is no need to stop the equipment and the next air pressure gradient experiment can be carried out directly. The controller 23 manages the inflation and deflation device to release helium and completes the adjustment of the initial value of the air pressure. As the air pressure decreases, the piston stroke will increase and will hit the cylinder again. The impact sensor 22 detects a signal, and the controller 23 adjusts the expansion chamber volume control device 15 and the back pressure chamber volume control device 16 again to shrink them at a ratio of 1:2, and repeats the process until the efficiency test of all air pressure gradients is completed.

[0044] In the efficiency test experiment with constant heating power, the startup and heating process are consistent with the efficiency test experiment with constant hot end temperature. The termination condition is changed to keep the heating power unchanged until the temperature of the expansion chamber 8 of the Stirling generator cannot be further increased. After the Stirling generator runs stably, the ratio of the output power of the first linear motor and the input power of the heater is calculated to complete the efficiency test under the current air pressure.

[0045] The present invention controls the expansion chamber housing 17 to move up and down in the axial direction of the intermediate housing 32 through the expansion chamber volume control device 15 to control the longitudinal length of the expansion chamber 8, and controls the back pressure chamber housing 18 to move up and down in the axial direction of the intermediate housing 32 through the back pressure chamber volume control device 16 to control the longitudinal length of the back pressure chamber 10, so that the longitudinal length of the Stirling generator can be variable, so as to adapt to the stroke changes of the gas distribution piston and the power piston caused by the change of the working air pressure. It is convenient to eliminate the influence of the gas distribution piston hitting the cylinder or the excessive dead volume on the experiment in the experiment of testing the influence of the inflation pressure on the efficiency of the free piston Stirling generator, provide convenience for the experimental operation, reduce the experimental cost, and save time and labor.

[0046] Those skilled in the art may make various modifications and variations to the present invention. If these modifications and variations are within the scope of the claims of the present invention and their equivalents, then these modifications and variations are also within the protection scope of the present invention.

[0047] The contents not described in detail in the specification are prior art known to those skilled in the art.

Claims

1. A variable volume electromagnetic spring Stirling generator for testing, characterized in that: It includes a Stirling generator body, an expansion chamber volume control device, a back-pressure chamber volume control device, an expansion chamber charging and discharging device, a back-pressure chamber charging and discharging device and a controller; the Stirling generator body includes a shell, a cylinder, a gas distribution piston, a power piston and an electromagnetic spring, the electromagnetic spring is connected to the gas distribution piston and the power piston, the shell includes an expansion chamber shell, an intermediate shell and a back-pressure chamber shell, the intermediate shell is a structure with two ends open, the expansion chamber shell is located above the intermediate shell and is sealed with the intermediate shell, the back-pressure chamber shell is located below the intermediate shell and is sealed with the intermediate shell; the cylinder is arranged in the intermediate shell, the gas distribution piston and the power piston are arranged in the cylinder from top to bottom, a connecting rod is arranged at the lower end of the gas distribution piston, the power piston is sleeved in the middle of the connecting rod, the space formed between the gas distribution piston and the expansion chamber shell is the expansion chamber, the space formed between the gas distribution piston and the power piston is the compression chamber, and the space formed between the power piston and the back-pressure chamber shell is the back-pressure chamber; The expansion chamber volume control device is arranged on the expansion chamber shell, and the expansion chamber volume control device can be used to control the expansion chamber shell to move up and down in the axial direction of the intermediate shell. The back pressure chamber volume control device is arranged on the back pressure chamber shell, and the back pressure chamber volume control device can be used to control the back pressure chamber shell to move up and down in the axial direction of the intermediate shell. An expansion chamber inflation valve is provided on the expansion chamber shell, and a back pressure chamber inflation valve is provided on the back pressure chamber shell. The expansion chamber inflation and deflation device is connected to the expansion chamber inflation valve, and the back pressure chamber inflation and deflation device is connected to the back pressure chamber inflation valve. The controller is respectively connected to the expansion chamber inflation and deflation device, the back pressure chamber inflation and deflation device, the expansion chamber volume control device, and the back pressure chamber volume control device.

2. The variable volume electromagnetic spring Stirling generator for testing according to claim 1, characterized in that: The sides of the expansion chamber shell and the back pressure chamber shell are both provided with a circle of grooves, and sealing elements are arranged in the grooves.

3. The variable volume electromagnetic spring Stirling generator for testing as claimed in claim 2, characterized in that: The sealing element comprises a sealing lip, a locking ring and a spring energizer. The locking ring and the spring energizer are arranged in the sealing lip, and the spring energizer is located between the sealing lip and the locking ring.

4. The variable volume electromagnetic spring Stirling generator for testing according to claim 1 or 2, characterized in that: An expansion chamber helium tank and a back pressure chamber helium tank are also provided. The expansion chamber helium tank is connected to the expansion chamber gas charging and discharging device, and the back pressure chamber helium tank is connected to the back pressure chamber gas charging and discharging device.

5. The variable volume electromagnetic spring Stirling generator for testing according to claim 1 or 2, characterized in that: The power piston and the gas distribution piston are both provided with displacement sensors; the expansion chamber shell is provided with an impact sensor.

6. The variable volume electromagnetic spring Stirling generator for testing according to claim 1 or 2, characterized in that: The Stirling generator body also includes a heater, a regenerator, and a cooler. The heater, the regenerator, and the cooler are arranged from top to bottom between the cylinder and the intermediate shell, and an insulating ring is arranged between the heater, the regenerator, the cooler and the intermediate shell.

7. The variable volume electromagnetic spring Stirling generator for testing according to claim 1, characterized in that: The electromagnetic spring includes a first linear motor, a second linear motor, an energy storage device, a converter and a frequency converter. The energy storage device is connected to the first linear motor through the converter, the first linear motor is connected to the frequency converter, and the frequency converter is connected to the second linear motor; the first linear motor is connected to the power piston, and the second linear motor is connected to the gas distribution piston.

8. The variable volume electromagnetic spring Stirling generator for testing according to claim 7, characterized in that: The first linear motor includes a first linear motor stator and a first linear motor mover. The first linear motor stator is fixed on the middle shell, and the first linear motor mover is fixed on the lower end of the power piston through a connecting bracket. The second linear motor includes a second linear motor stator and a second linear motor mover. The second linear motor stator is fixed on the middle shell through a connecting bracket, and the second linear motor mover is sleeved on the lower end of the valve piston connecting rod.

9. The variable volume electromagnetic spring Stirling generator for testing according to claim 7 or 8, characterized in that: The first linear motor and the second linear motor are disposed in the back pressure chamber.

10. The variable volume electromagnetic spring Stirling generator for testing according to claim 1 or 2, characterized in that: A fixing frame is also provided, and the Stirling generator body, the expansion chamber volume control device, and the back pressure chamber volume control device are arranged in the fixing frame, the expansion chamber volume control device is connected between the fixing frame and the expansion chamber shell, and pushes the expansion chamber shell to control the longitudinal length of the expansion chamber; the back pressure chamber volume control device is connected between the fixing frame and the back pressure chamber shell, and pushes the back pressure chamber shell to control the longitudinal length of the back pressure chamber.

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