Micro-electric propulsion storage and supply system

Abstract

The application discloses a micro electric propulsion storage and supply system, characterized in that the system comprises a storage module, a pressure regulating module, a flow regulating module, a power module and a control module, wherein the storage module, the pressure regulating module and the flow regulating module are sequentially connected through stainless steel pipelines, and the modules and the pipelines are connected through standard sleeves; the power module supplies power to the pressure regulating module and the flow regulating module, and the control module realizes pressure and flow control. The system adopts a combination of a miniature mechanical pressure reducing valve and a pressure sensor as the pressure regulating module, realizes smaller volume and mass relative to a Bang-Bang type, and has lower cost relative to a proportional type, so that balance is achieved between the reduction of the volume and mass of the system and economy; the flow regulating module adopts a pasting mode of a capillary tube and a silicon rubber heating belt, so that the silicon rubber heating belt can be directly pasted to the metal capillary tube, and an outer shell of the capillary tube is not needed, thereby reducing the volume and mass of the module and improving the heating efficiency.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of propellant gas supply of micro storage and supply system in propulsion technology, and particularly relates to a micro electric propulsion storage and supply system suitable for micro-satellite tasks. BACKGROUND

[0002] With the continuous development of aerospace power technology, electric propulsion has been widely used in north-south position keeping and orbit transfer type space missions due to its characteristics of high specific impulse, long life, small thrust, high control accuracy and the like. In recent years, a large number of micro-satellite near-earth and deep space exploration missions have emerged, which provides new application occasions for electric propulsion technology and also puts forward new requirements for electric propulsion systems.

[0003] The storage and supply system is one of the electric propulsion subsystems, mainly including propellant storage, pressure regulation and flow regulation modules, and undertakes the functions of storing propellant and supplying downstream electric thrusters. The traditional storage and supply system, taking large satellite missions as the background, often follows the design concept of chemical propulsion systems, and has a large volume and weight while achieving micro-flow supply (0.01-10 mg / s). This not only contradicts the requirements of micro-satellite platforms, but also makes it difficult to fully realize the advantages of high specific impulse of electric propulsion.

[0004] At present, common micro electric propulsion storage and supply systems can be divided into two types according to different pressure regulation modules:

[0005] (1) The traditional Bang-Bang type storage and supply system (such as Figure 1 ) controls the pressure by adjusting the opening and closing of multiple series electromagnetic valves, attenuates the pressure fluctuation in the buffer tank after the valve to the required pressure range, and then outputs the target flow through the flow regulation effect of the throttle.

[0006] The improved Bang-Bang type (such as Figure 2 ) pressure module includes an electromagnetic valve, a pressure reducing valve, a buffer tank, a charge and discharge valve, and a low-pressure sensor, and the system adjusts the opening and closing of a single electromagnetic valve according to the pressure in the buffer tank. The propellant gas flows to the flow control module after being reduced by the pressure reducing valve. Its advantages are that the structure of the pressure module is simplified, and the mass and volume of the module are reduced; the disadvantage is that the system still needs a large number of repeated opening and closing of the electromagnetic valve to regulate the pressure, and the service life of the electromagnetic valve is limited.

[0007] (2) The typical structure of the proportional type storage and supply system is shown in Figure 3 , which adopts a proportional flow control valve (PFCV) in the pressure regulation module. The low-pressure pressure sensor at the downstream provides feedback to the proportional / integral controller (PI), which adjusts the current of the PFCV to change the valve opening to provide the required pressure. The regulated propellant gas will be supplied to the thruster at a constant flow rate through the flow regulation of the throttle hole.

[0008] The advantage of the proportional micro-electric propulsion feed system is that the pressure regulating module can realize the precise and continuous control of the downstream pressure, and the pressure regulating precision is high. However, the non-linear problems such as the dead zone, creep and heat of the proportional valve bring difficulties to the control, and the cost of the proportional valve is relatively high, which has a certain influence on the economy of the system.

[0009] In addition, the feed system can also be classified according to different flow regulating modules. The capillary type flow regulating module is widely used in engineering and is one of the most successful types. The miniaturized capillary throttling element is also developed in the micro-electric propulsion feed system, and a typical structure is shown in Figure 4 The capillary type flow control module winds the capillary on a cylindrical block and accommodates it in a shell. The shell is connected with a heater, and the viscosity of the gas in the pipe is controlled by electric heating of the capillary to regulate the flow size. The advantages are high reliability, low cost and light weight; the disadvantages are that the heater cannot be directly connected to the capillary due to the use of a capillary with a smaller diameter, and a shell is designed, which makes the structure more complex, increases the mass of the module and reduces the heating efficiency.

[0010] In summary, for the design of the micro-electric propulsion feed system, the disadvantages and problems are as follows:

[0011] 1. The volume and weight of the micro-electric propulsion system need to be limited within a certain range. The pressure regulating module of the traditional electric propulsion feed system generally adopts Bang-Bang type or proportional type: Bang-Bang type needs multiple electromagnetic valves and buffer tanks and other components, and the structure is complex, occupies more space, has large weight, and is limited by the service life of the electromagnetic valve; and the economic cost of the proportional type is too high, and the economy is difficult to accept for low-cost microsatellite missions;

[0012] 2. When the micro-electric propulsion feed system uses the "micro-capillary + silicone rubber thermal control" mode, the direct attachment of the heating device to the pipe wall is difficult due to the too thin micro-capillary, and a metal shell needs to be installed outside the capillary. The shell heats the working medium in the capillary to control the flow, but the shell increases the weight and volume of the system and also reduces the heating efficiency.

[0013] Therefore, under the premise of meeting the demand of the electric thruster, it is of great engineering significance to improve the design of each module of the micro-electric propulsion feed system to realize low cost, miniaturization and light weight. SUMMARY

[0014] In order to solve the above problems, the application proposes a micro mechanical pressure regulating module scheme, realizes smaller volume and mass compared with Bang-Bang type, and lower cost compared with proportional type, and balances between reducing system volume and mass and economy; the application designs the attachment mode of the capillary and the silicone rubber heater in the flow regulating module, so that the silicone rubber heater can be directly attached to the metal capillary, without the capillary shell, reduces the module volume and mass, and improves the heating efficiency.

[0015] In order to achieve a better balance between reducing system volume and mass and improving economy, the application designs a micro mechanical pressure reducing valve and a pressure sensor combination as a pressure regulating module. This scheme reduces the components of the pressure regulating module, reduces the module mass (the module mass is less than 200g, including the connecting piece), and reduces the space occupied by the module. The upstream and downstream of the micro mechanical pressure reducing valve are respectively provided with high pressure and low pressure pressure sensors to detect the pressures before and after the valve. By adjusting the vertical rod position of the pressure reducing valve, the pre-compression amount of the spring and diaphragm can be changed to achieve different pre-tightening forces. The pre-tightening force and the upstream and downstream gas pressure jointly act on the valve core position to achieve balance. The pressure negative feedback regulation mechanism of the mechanical pressure reducing valve itself realizes that the upstream high pressure working medium is reduced to the expected value (usually in the range of 0.1-0.4MPa) through the pressure reducing valve and remains stable. At the same time, the cost of the module in the application is also much lower than that of the proportional type.

[0016] In order to realize the direct attachment of the silicone rubber heater and the capillary in the flow regulating module to avoid the capillary shell design, the application designs a coil structure, which winds the slender capillary to form a three-section capillary closely adjacent and overlapping structure. The silicone rubber heater is designed in a strip shape, and the strip-shaped silicone rubber heater is spirally wound at the coil overlapping position and fixed with high-temperature adhesive tape. When the silicone rubber heater is powered on, it can directly heat the capillary, improve the working medium temperature, change the viscosity, and then realize the working medium mass flow regulation.

[0017] The application specifically adopts the following technical scheme:

[0018] A micro electric propulsion storage and supply system, comprising: a storage module, a pressure regulating module, a flow regulating module, a power module, and a control module, wherein the storage module, the pressure regulating module, and the flow regulating module are connected in sequence through a stainless steel pipeline, and the modules and the pipeline are connected through a standard sleeve; the power module supplies power to the pressure regulating module and the flow regulating module; the control module collects pressure and flow signals, and realizes flow control through temperature regulation.

[0019] Preferably, the storage module comprises a carbon fiber gas cylinder, a straight-through valve and a first self-locking valve, wherein the carbon fiber gas cylinder 1 is used for storing high-pressure gas, the straight-through valve is used for opening and closing control when the gas cylinder is filled with working gas, and the straight-through valve remains open during system operation; the first self-locking valve is used for opening and closing control of the supply of working gas from the gas cylinder to the pressure regulating module.

[0020] Preferably, the pressure regulating module comprises a high-pressure pressure sensor, a micro-mechanical pressure reducing valve and a low-pressure pressure sensor connected in sequence, wherein the high-pressure pressure sensor is used for detecting the pressure before the micro-mechanical pressure reducing valve, and the low-pressure pressure sensor is used for detecting the pressure after the micro-mechanical pressure reducing valve; by adjusting the vertical rod position of the micro-mechanical pressure reducing valve to change the pre-compression amount of the spring and diaphragm to achieve different pre-tightening forces, the pre-tightening forces and the upstream and downstream gas working pressures jointly act on the valve core position to achieve balance.

[0021] Preferably, the flow regulating module comprises a silicon rubber heating strip, a stainless steel capillary tube, a second self-locking valve and a mass flow sensor, wherein the upstream of the stainless steel capillary tube is connected with the pressure regulating module, the downstream is connected with the second self-locking valve and the mass flow sensor in sequence, the second self-locking valve is used for controlling the supply of working gas to the downstream thruster or cathode, and the mass flow sensor is used for flow monitoring; the stainless steel capillary tube is coiled to form a three-section capillary tube closely adjacent overlapping structure, the silicon rubber heating strip is spirally wound at the overlapping structure of the coil and fixed with high-temperature adhesive tape, the silicon rubber heating strip directly heats the capillary tube after being powered on, the temperature of the gas working medium in the capillary tube is increased to change its viscosity, and the mass flow of the working medium is regulated.

[0022] Preferably, the power module comprises a power processing unit for supplying power to the first self-locking valve, the second self-locking valve, the high-pressure pressure sensor, the low-pressure pressure sensor and the mass flow sensor.

[0023] Preferably, the control module comprises a computer control system and a PID temperature controller, the computer control system is used for collecting data of the high-pressure pressure sensor, the low-pressure pressure sensor and the mass flow sensor to realize pressure and flow monitoring control; and the PID temperature controller is used for temperature control of the silicon rubber heating strip.

[0024] Preferably, a metal filter and a variable diameter sleeve are arranged between the pressure regulating module and the flow regulating module, and the low-pressure pressure sensor, the metal filter, the variable diameter sleeve and the stainless steel capillary tube are connected in sequence.

[0025] Compared with the prior art, the present application has the following beneficial effects:

[0026] 1. The pressure regulating module of the storage system in the application adopts a micro-mechanical type, has low cost, requires a small number of components, has small module quality, occupies less space, and makes up for the shortcomings of Bang-Bang and proportional types in the field of micro-satellite tasks.

[0027] 2. The flow regulating module eliminates the design of the capillary tube shell, reduces the module quality and volume, improves the heating efficiency of the heater, and shortens the response time of flow regulation.

[0028] 3. The whole system is built with standard stainless steel pipes and sleeves, has a standard connecting piece, is fast and quick to process and install, can be adjusted, replaced and added according to actual conditions, has wide applicability, and has low system cost.

[0029] 4. The related design and method of the application can also be referenced and promoted in other micro-electric propulsion storage systems. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the drawings needed in the embodiments will be briefly introduced below, and the features and advantages of the application can be more clearly understood by referring to the drawings. The drawings are schematic and should not be understood as any limitation on the application. For those skilled in the art, other drawings can be obtained without creative labor on the basis of these drawings.

[0031] Figure 1 for a typical Bang-Bang type storage system in the prior art;

[0032] Figure 2 for an improved Bang-Bang type storage system in the prior art;

[0033] Figure 3 for a typical proportional type storage system in the prior art;

[0034] Figure 4 for a typical capillary flow regulating module in the prior art;

[0035] Figure 5 for a schematic diagram of the overall structure of the application;

[0036] Figure 6 for a schematic diagram of the coiled capillary tube and heater in the flow regulating module of the application;

[0037] Figure 5 and Figure 6In the middle: 1-Carbon fiber gas cylinder; 2-Straight-through valve; 3-Angle ferrule; 4-Power processing unit; 5-Computer control system; 6-First self-locking valve; 7-High pressure sensor; 8-Miniature mechanical pressure reducing valve; 9-Low pressure sensor; 10-Metal filter; 11-Variable diameter ferrule; 12-Silicone rubber heating belt; 13-Stainless steel capillary tube; 14-Second self-locking valve; 15-Mass flow sensor; 16-PID temperature controller. Detailed Implementation

[0038] The technical solution of the present invention will now be described in detail with reference to the accompanying drawings.

[0039] A micro-electric propulsion storage and supply system, such as Figure 5 As shown, it includes a storage module, a pressure regulation module, a flow regulation module, a power supply module, and a control module. The storage module, pressure regulation module, and flow regulation module are connected in sequence via stainless steel pipes, and the modules and pipes are connected by standard compression fittings. The power supply module supplies power to the pressure regulation module and the flow regulation module, and the control module collects pressure and flow signals and achieves flow control through temperature regulation.

[0040] Specifically, the storage module includes a carbon fiber gas cylinder 1, a straight-through valve 2, and a first self-locking valve 6. The carbon fiber gas cylinder 1 is used to store high-pressure gas, the straight-through valve 2 is used for switching control when the gas cylinder is filled with working gas, the straight-through valve remains open when the system is working, and the first self-locking valve 6 is used for switching control of the gas cylinder supplying working gas to the pressure regulating module.

[0041] The pressure regulation module includes a high-pressure sensor 7, a miniature mechanical pressure reducing valve 8, and a low-pressure sensor 9 connected in sequence. The high-pressure sensor 7 detects the inlet pressure of the miniature mechanical pressure reducing valve 8, and the low-pressure sensor 9 detects the outlet pressure of the miniature mechanical pressure reducing valve 8. By adjusting the position of the vertical rod of the miniature mechanical pressure reducing valve 8, the pre-compression of the spring and diaphragm can be changed to achieve different pre-tightening forces. The pre-tightening force, together with the upstream and downstream gas working fluid pressures, acts at the valve core position to achieve balance. The pressure negative feedback regulation mechanism of the miniature mechanical pressure reducing valve 8 ensures that the upstream high-pressure working fluid is reduced to the expected value (typically within the range of 0.1–0.4 MPa) and remains stable after passing through the pressure reducing valve. Compared to the mechanical pressure reducing valves in traditional large-scale storage and supply systems, the miniature mechanical pressure reducing valve 8 weighs less than 80g, with an envelope size of 27mm × 27mm × 35mm.

[0042] The flow regulating module comprises a silicon rubber heating belt 12, a stainless steel capillary tube 13, a second self-locking valve 14 and a mass flow sensor 15, wherein the upstream of the stainless steel capillary tube 13 is connected with the pressure regulating module, the downstream is sequentially connected with the second self-locking valve 14 and the mass flow sensor 15, the second self-locking valve 14 is used for controlling the supply of working gas to the downstream thruster or cathode, and the mass flow sensor 15 is used for flow monitoring. Figure 2 The coil structure as shown in the figure is designed, the elongated capillary tube is coiled to form a three-section capillary tube closely adjacent and overlapped structure, the silicon rubber heating belt 12 is designed in the form of a strip, and the strip-shaped silicon rubber heating belt 12 is spirally wound at the coil overlapping position and is fixed by high-temperature adhesive tape. When the silicon rubber heating belt 12 is powered, the capillary tube 13 can be directly heated, the working gas temperature is increased to change the viscosity and thus the working gas mass flow is regulated.

[0043] The power module comprises a power processing unit 4, which is used for supplying power to the first self-locking valve 6, the second self-locking valve 14, the high-pressure pressure sensor 7, the low-pressure pressure sensor 9 and the mass flow sensor 15.

[0044] The control module comprises a computer control system 5 and a PID temperature controller 16, the computer control system 5 is used for collecting the data of the high-pressure pressure sensor 7, the low-pressure pressure sensor 9 and the mass flow sensor 15 to realize pressure and flow monitoring control, and the PID temperature controller 16 is used for temperature control of the silicon rubber heating belt 12.

[0045] Further, in order to better connect the pressure regulating module and the flow regulating module and filter the gas, a metal filter 10 and a variable-diameter sleeve 11 can also be arranged, and the low-pressure pressure sensor 9, the metal filter 10, the variable-diameter sleeve 11 and the stainless steel capillary tube 13 are sequentially connected.

[0046] The working process of the micro-electric propulsion storage and supply system is as follows:

[0047] 1. The gas working substance is depressurized and stabilized by the micro-mechanical pressure regulating module.

[0048] The gas working substance stored in the high-pressure carbon fiber gas cylinder 1 reaches the valve core of the micro-mechanical pressure regulating valve 8 through the pipeline after the first self-locking valve 6 is opened (which is kept open during the working process). The pre-tightening force of the spring and the diaphragm can be determined by pre-setting the vertical rod position of the pressure regulating valve. When the high-pressure gas passes through the valve port, it is depressurized by throttling, and when the gas pressure and the pre-tightening force tend to be balanced, the valve core no longer moves, that is, the throttling area no longer changes. Stable low-pressure gas flows from the valve port to the downstream pipeline. The high-pressure pressure sensor 7 and the low-pressure pressure sensor 9 are used for pressure monitoring in the pre-setting and normal working stages.

[0049] 2. The gas working substance realizes flow regulation function through the heat capillary.

[0050] The low-pressure gas flows to the heat capillary 13, and realizes the effect of flow reduction due to the throttling effect of the reduced flow area. The length and diameter of the capillary directly determine the size of the flow of the gas after regulation, and the detailed parameters can be determined according to the pre-experiment of the electric thruster demand. When the gas working substance flows in the capillary, the heater heats the gas through the pipe wall, and the temperature change causes the viscosity change to realize the thermal regulation of the working substance flow, so as to meet the system demand with high precision. Among them, the heater adopts PID control, and the mass flow sensor 15 is used for flow monitoring in the pre-experiment and normal working stage.

[0051] In the present application, unless specifically defined otherwise or limited differently, the terms "mounting", "connecting", "connecting", "fixing" and the like should be broadly understood, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication between two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0052] In the present application, unless specifically defined otherwise or limited differently, the first feature "on" or "under" the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the first feature "on", "above" and "above" the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0053] In the present application, the terms "first", "second", "third", "fourth" are only for descriptive purposes and should not be construed or implied to indicate or imply relative importance. The term "a plurality of" means two or more, unless otherwise specifically limited.

[0054] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A micro-electric propulsion storage and supply system, characterized in that, include: The system comprises a storage module, a pressure regulation module, a flow regulation module, a power supply module, and a control module. The storage module, pressure regulation module, and flow regulation module are connected sequentially via stainless steel pipes, and are connected to the pipes via standard compression fittings. The power supply module supplies power to the pressure regulation module and the flow regulation module, and the control module acquires pressure and flow signals and achieves flow control through temperature regulation. The storage module includes a carbon fiber gas cylinder, a straight-through valve, and a first self-locking valve. The carbon fiber gas cylinder is used to store high-pressure gas, the straight-through valve is used to control the opening and closing of the gas cylinder when it is filled with working gas, the straight-through valve remains open when the system is working, and the first self-locking valve is used to control the opening and closing of the gas cylinder supplying working gas to the pressure regulating module. The pressure regulation module includes a high-pressure sensor, a micro-mechanical pressure reducing valve, and a low-pressure sensor connected in sequence. The high-pressure sensor is used to detect the gas pressure before the valve of the micro-mechanical pressure reducing valve, and the low-pressure sensor is used to detect the gas pressure after the valve of the micro-mechanical pressure reducing valve. By adjusting the position of the vertical rod of the micro-mechanical pressure reducing valve, the pre-compression of the spring and diaphragm is changed to achieve different pre-tightening forces. The pre-tightening force and the upstream and downstream gas working fluid pressure work together at the valve core position to achieve balance. The flow regulation module includes a silicone rubber heating belt, a stainless steel capillary tube, a second self-locking valve, and a mass flow sensor. The upstream end of the stainless steel capillary tube is connected to the pressure regulation module, and the downstream end is sequentially connected to the second self-locking valve and the mass flow sensor. The second self-locking valve is used to control the supply of working gas to the downstream thruster or cathode, and the mass flow sensor is used for flow monitoring. The stainless steel capillary tube is coiled to form a three-section overlapping structure with close proximity. A strip-shaped silicone rubber heating belt is spirally wound at the overlapping structure of the coil and fixed with high-temperature tape. When the silicone rubber heating belt is energized, it directly heats the capillary tube, increasing the temperature of the working gas in the capillary tube to change its viscosity, thereby achieving the regulation of the working gas mass flow rate.

2. The micro-electric propulsion storage and supply system according to claim 1, characterized in that, The power module includes a power processing unit for supplying power to the first self-locking valve, the second self-locking valve, the high-pressure sensor, the low-pressure sensor, and the mass flow sensor.

3. A micro-electric propulsion storage and supply system according to claim 2, characterized in that, The control module includes a computer control system and a PID temperature controller. The computer control system is used to collect data from the high-pressure sensor, low-pressure sensor, and mass flow sensor to achieve pressure and flow monitoring and control. The PID temperature controller is used for temperature control of the silicone rubber heating belt.

4. A micro-electric propulsion storage and supply system according to claim 3, characterized in that, A metal filter and a variable diameter ferrule are provided between the pressure regulating module and the flow regulating module. The low-pressure sensor, the metal filter, the variable diameter ferrule, and the stainless steel capillary tube are connected in sequence.

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