A grid-connected voltage control method for spacecraft rendezvous and docking

Abstract

The present invention relates to a grid-connected voltage control method for spacecraft rendezvous and docking, comprising: S100, the combined spacecraft transforms the signal input from the busbar to the docking mechanism through the grid-connected controller; S200, remote signal sampling is performed on the docking mechanism; S300, the remote sampling signal is fed back to the grid-connected controller; S400, the grid-connected controller adjusts the voltage of the output signal according to the remote sampling signal and outputs the adjusted signal; S500, the docking mechanism receives the adjusted signal and transmits it to the load through a floating disconnector. By setting the sampling feedback point of the grid-connected voltage control on the docking mechanism of the combined spacecraft, close to the floating disconnector and the load aircraft, high-precision and long-life grid-connected voltage control can be achieved, and the original structure of the combined spacecraft is not affected, so that low cost is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of spacecraft, and in particular to a grid-connected voltage control method for spacecraft rendezvous and docking. Background Art

[0002] The grid-connected system is an important component of the energy system of the combined spacecraft. It undertakes the important function of realizing the power grid connection between the combined spacecraft and the visiting spacecraft. After the visiting spacecraft docks, it will be affected by its flight posture and obstruction, resulting in insufficient power generation capacity. The combined spacecraft will provide the visiting spacecraft with stable and continuous power supply through grid-connected power supply to ensure the energy balance and energy security of the visiting spacecraft.

[0003] The physical connection between the combined spacecraft and the visiting spacecraft for rendezvous and docking is achieved through a standard docking mechanism. The grid power supply interface is a circuit floating disconnector on the docking mechanisms of the two spacecraft. The combined spacecraft must ensure the voltage accuracy characteristics of the interface to ensure that the characteristics of the grid power supply output bus between the two models match those of the visiting spacecraft bus. Especially for long-life combined spacecraft, the docked manned visiting spacecraft has put forward high-precision requirements that are about one order of magnitude higher than the previous grid power supply voltage accuracy. At the same time, it is necessary to ensure that the voltage accuracy is stable after more than 10 years of in-orbit operation. Compared with the networking power supply of internal cabins of previous satellites and short-term missions, the technical difficulty has been greatly increased, and special designs need to be carried out to achieve the working characteristics requirements of high-precision voltage control under long life. At the same time, it is necessary to avoid a significant increase in research and development and testing funds due to the transformation of large equipment such as general docking mechanisms, and solve practical engineering problems through low-cost technical solutions.

[0004] The International Space Station is a typical combined spacecraft that uses a power grid system, but its system design does not involve the use of high-precision voltage control. my country's manned space flight conducted preliminary attempts to connect power to the grid in the second phase. Currently, the grid connection adopts a proximal constant voltage control method. When the power is about 500W, the interface output voltage is significantly affected by the cable voltage drop. When the bus voltage of the visiting spacecraft changes, the grid current will change significantly, increasing the bus safety risk. At present, in the process of exploring the constant current grid-connected power supply mode, a design method based on a constant current voltage-limited power converter to realize grid-connected power supply between two high-voltage system spacecraft has been proposed, but the design and implementation of high-precision voltage control has not been carried out.

[0005] The combined spacecraft and the visiting manned spacecraft generally use a 28V grid-connected power supply interface. Due to the large size of the cabin, there is a grid-connected power supply cable transmission of more than 20m between the grid-connected output device and the busbar receiving the power supply. At the same time, the visiting manned spacecraft has put forward a high-precision requirement for the voltage control accuracy that the voltage stability is better than ±1.25% under the power fluctuation of 1.5KW of the power supply interface within the full life cycle of 10 years, which is not achievable for the traditional proximal constant voltage control method. The important difference between the development of spacecraft and general ground equipment is that the weight and volume are greatly restricted. Therefore, although the most direct solution to improve voltage accuracy is to reduce the resistance of the grid-connected power supply cable, under the premise that the cable length cannot be reduced due to a certain distance, the only way is to increase the cable diameter and increase the number of contacts. However, both methods will cause the status of the equipment and cables to change, and require a lot of cable weight. In actual engineering, it is impossible to install and lay so many cables or cause the system weight to exceed the standard. The combined spacecraft has the characteristics of long life, and the design of voltage control must also adapt to the accuracy loss caused by the time drift of equipment device parameters after long life, which must be effectively controlled in circuit design. Another way to improve control accuracy is to increase the cable voltage drop compensation coefficient in the software. However, since the cable resistance and device time drift are constantly changing due to the influence of the working environment temperature and the spacecraft's time in orbit, it is necessary to determine the influencing factors under various working conditions throughout the life cycle during the development of a single machine. This makes it almost impossible to achieve high-precision control during engineering design implementation.

[0006] In terms of the specific implementation of remote voltage feedback, the previous method of adding sampling points is to add special equipment at the designated location, obtain sampling signals through sampling circuits such as Hall, and then transmit them back to the voltage controller to achieve closed-loop control. This method requires additional equipment and installation space, and requires the modification of the general docking mechanism, which has a high implementation cost. At the same time, since the power supply interface between the combined spacecraft and the visiting aircraft is located on the docking mechanism, the location of the sampling special equipment cannot be close to the docking surface, and the feedback voltage is quite different from the power supply interface voltage, and the control accuracy still cannot meet the requirements. Summary of the invention

[0007] In view of this, the present invention aims to propose a grid-connected voltage control method for spacecraft rendezvous and docking under the above-mentioned problems and engineering implementation constraints, and to solve the problems of low grid-connected voltage control accuracy, short life and high cost under large-range fluctuations in the load of visiting aircraft, based on a grid-connected power supply voltage control method with low cost remote sampling.

[0008] The embodiment of the present invention provides a grid-connected voltage control method for spacecraft rendezvous and docking, and the grid-connected voltage control method includes:

[0009] S100, the combined spacecraft transforms the signal input from the busbar and outputs it to the docking mechanism through the grid-connected controller;

[0010] S200, performing remote signal sampling on the docking mechanism;

[0011] S300, feeding back the remote sampling signal to the grid-connected controller;

[0012] S400, the grid-connected controller adjusts the voltage of the output signal according to the remote sampling signal and outputs it as the adjusted signal;

[0013] S500: The docking mechanism receives the adjusted signal and transmits it to the load through a floating disconnector.

[0014] According to one aspect of the present invention, an expansion point module is provided on the internal cable of the docking mechanism, and the expansion point module samples the remote signal and feeds it back to the grid-connected controller.

[0015] According to one aspect of the present invention, in S100, the signal input by the busbar is output to the docking mechanism through the grid-connected output cable of the combined spacecraft, and the docking mechanism includes a connector for connecting to the grid-connected output cable, and the connector is connected to the expansion module. The connector is also connected to the grid-connected controller through the signal transmission cable in the docking mechanism and the transmission cable in the cabin of the combined spacecraft.

[0016] According to one aspect of the present invention, the expansion point module is D436.

[0017] According to one aspect of the present invention, the distance between the expansion point module and the floating disconnector is less than or equal to 0.2 meters.

[0018] According to one aspect of the present invention, the floating disconnect includes a passive floating disconnect provided on the docking mechanism and an active floating disconnect for connecting to the load.

[0019] According to one aspect of the present invention, the grid-connected controller includes a high-precision voltage control circuit, which includes a voltage divider circuit composed of five-stage voltage divider resistors connected in series. The remote sampling signal clamps the total voltage of the second, third and fourth stage voltage divider resistors and obtains an effective feedback voltage signal through the second, third and fourth stage voltage divider resistors, which is then sent to the converter control circuit through the operational amplifier conditioning circuit.

[0020] According to one aspect of the present invention, in S400, the grid-connected controller adjusts the voltage of the output signal according to the feedback signal, and uses the digital-to-analog conversion output as a reference for voltage conversion, specifically including:

[0021] S410, calculating the accuracy deviation introduced by the sampling resistor, the time drift and the temperature drift of the AD device in the analog circuit and the voltage selection accuracy, and obtaining the maximum forward deviation and the maximum reverse deviation of the voltage;

[0022] S420, determining a voltage adjustment gear interval according to a maximum forward deviation and a maximum reverse deviation of the voltage;

[0023] S430, injecting the gear interval specified voltage into an instruction table, and adding a voltage setting instruction to a system instruction computer of the combined spacecraft;

[0024] S440, the grid-connected controller receives a voltage injection instruction from an upstream computer, parses and outputs an 8-bit digital signal and a 1-bit low-level valid latch pulse signal, and sets an output voltage value of the power component;

[0025] S450, the power component converts the 8-bit digital signal into an analog voltage signal through a DA conversion circuit, and sends the analog voltage signal to the converter control circuit as a voltage control reference.

[0026] According to one aspect of the present invention, the voltage adjustment gear interval is 0.02V.

[0027] The embodiment of the present invention sets the sampling feedback point of the grid-connected voltage control on the docking mechanism of the combined spacecraft, close to the floating disconnector and the load aircraft, and designs a high-precision voltage control circuit inside the grid-connected controller, and designs and implements a signal sampling and control method, which can achieve high-precision and long-life grid-connected voltage control, and can ensure that under the condition of an on-orbit life of more than 10 years, under the condition of large power fluctuations of the visiting aircraft load, the grid-connected power supply voltage output stability of the combined spacecraft is controlled within ±1.25%, and there is no need to add equipment or additional installation space on the basis of the existing spacecraft structure, and the original structure of the combined spacecraft is not affected, thereby achieving low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only 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 A schematic diagram of a flow chart of a grid-connected voltage control method according to an embodiment of the present invention;

[0030] Figure 2 A schematic diagram of the principle of a grid-connected voltage control method according to an embodiment of the present invention;

[0031] Figure 3 A schematic diagram of connection and transmission of an expansion point module according to an embodiment of the present invention;

[0032] Figure 4 A topological schematic diagram of a high-precision voltage control circuit according to an embodiment of the present invention;

[0033] Figure 5 Schematic diagram of a converter control circuit according to an embodiment of the present invention. DETAILED DESCRIPTION

[0034] The description of the embodiments of this specification should be combined with the corresponding drawings, which should be considered as part of the complete specification. In the drawings, the shape or thickness of the embodiments may be enlarged and indicated for simplification or convenience. Furthermore, the parts of each structure in the drawings will be described separately. It is worth noting that the elements not shown in the drawings or not described in words are in a form known to ordinary technicians in the relevant technical field.

[0035] The description of the embodiments herein and any reference to directions and orientations are only for the convenience of description and are not to be construed as any limitation on the scope of protection of the present invention. The following description of the preferred embodiments may involve combinations of features, which may exist independently or in combination, and the present invention is not particularly limited to the preferred embodiments. The scope of the present invention is defined by the claims.

[0036] like Figure 1 FIG. 1 is a flow chart of a grid-connected voltage control method according to an embodiment of the present invention, wherein the grid-connected voltage control method comprises:

[0037] S100, the combined spacecraft transforms the signal input from the busbar and outputs it to the docking mechanism through the grid-connected controller;

[0038] S200, performing remote signal sampling on the docking mechanism;

[0039] S300, feeding back the remote sampling signal to the grid-connected controller;

[0040] S400, the grid-connected controller adjusts the voltage of the output signal according to the remote sampling signal and outputs it as the adjusted signal;

[0041] S500: The docking mechanism receives the adjusted signal and transmits it to the load through a floating disconnector.

[0042] like Figure 2 , which is a schematic diagram of the principle of the grid-connected voltage control method according to an embodiment of the present invention.

[0043] Combination Figure 1 and Figure 2 :

[0044] In S100, the combined spacecraft transforms the bus input signal through the grid controller and outputs it to the docking mechanism. In this embodiment, the combined spacecraft transforms the 100V bus input into a 28V power output through the grid controller, wherein the 100V input bus can be any number, and two are shown in the figure. A grid output cable is also provided between the combined spacecraft and the docking mechanism, and the grid output cable can be one or more in series. The 100V bus is output by the grid controller and transmitted to the docking mechanism through the grid output cable.

[0045] In S200, remote signal sampling is performed on the docking mechanism. Figure 3 As shown, in this embodiment, an expansion module is provided on the internal cable of the docking mechanism, and the expansion module may be D436. The expansion module D436 is used for remote signal sampling and feeding back the sampled signal to the grid-connected controller.

[0046] In S300, the sampling signal is fed back to the grid-connected controller. Figure 3 As shown, in this embodiment, the docking mechanism has a connector Y27A for connecting to the grid-connected output cable, the connector Y27A is connected to the expansion module D436, and the connector Y27A is also electrically connected to the grid-connected controller through the signal transmission cable in the docking mechanism and the transmission cable in the cabin of the combined spacecraft. Figure 3 The middle dotted line represents the feedback path of the remote sampling signal, namely, signal 57, signal 58, signal 60 and signal 61. The signal is transmitted from connector Y27A to expansion module D436 (e.g., signal 52, signal 53) and returned to connector Y27A (e.g., signal 57, signal 58) after sampling. Connector Y27A transmits the signal through the signal transmission cable in the docking mechanism and the transmission cable in the cabin of the combined spacecraft ( Figure 2 The middle dotted line “remote sampling feedback” path) is fed back to the grid-connected controller.

[0047] Preferably, considering the internal structure of the docking mechanism, the cable direction and the minimum bending radius of the cable, the distance between the sampling point and the floating disconnector is less than or equal to 0.2 meters, that is, the distance between the expansion point module and the floating disconnector is less than or equal to 0.2 meters.

[0048] In S400, the grid-connected controller adjusts the voltage of the output signal according to the feedback signal and outputs the adjusted signal, which needs to meet the high-precision problem of voltage adjustment under long-term use conditions (such as 10 years).

[0049] like Figure 4As shown in the figure, in order to solve the problem of high-precision voltage control, in this embodiment, the grid-connected controller adopts a high-precision voltage control circuit. The specific implementation method is as follows: (a) the sampling point position is selected. According to the principle of proximity, the closer the sampling point is to the interface (the interface is the floating disconnector), the higher the voltage control accuracy is. The sampling point is selected to be close to the floating disconnector on the cable inside the docking mechanism. Considering the turning radius of the cable and the installation routing margin, the sampling point is no more than 200mm away from the floating disconnector cable; (b) the signal transmission path of the voltage feedback is designed. The principle of simplifying the transmission path is adopted. After sampling in the docking mechanism, it is directly sent to The grid-connected controller is designed to transmit the sampling point in the docking mechanism → the voltage signal cable in the docking mechanism → the equipment connector → the signal cable in the cabin → the internal circuit of the grid-connected controller; (c) The remote signal processing circuit in the grid-connected controller is designed. The principle of compatible design is adopted. On the basis of the proximal sampling circuit, a remote sampling control access circuit based on resistor voltage division is added to form a voltage division circuit with 5 levels of resistors in series (i.e., R1 to R5). After the remote sampling switch is turned on, the voltage obtained by remote sampling clamps the total voltage of the 2nd to 4th level voltage division resistors, and the effective feedback voltage is obtained by voltage division between the 2nd to 4th level resistors, and then the operational amplifier conditioning circuit ( Figure 4 The left side of the middle part) is sent to the converter control circuit ( Figure 2 (internal circuit of the converter module).

[0050] The control signal processing circuit adopts a circuit topology that combines proximal sampling feedback and remote sampling feedback. The proximal sampling feedback circuit is responsible for realizing the voltage control of the single machine startup, and the remote sampling feedback circuit is responsible for realizing the voltage control during grid-connected power transmission. The two sets of circuits reuse part of the circuit to form the same feedback signal and then send it to the converter control circuit. The use of remote sampling in each module of the power component can ensure that the voltage value of the sampling point is always consistent with the voltage value of the actual grid-connected point, and place the voltage drop loss on the cable in the voltage closed loop to compensate for the voltage drop on the cable when high power is output, causing the grid-connected point voltage to drop. Switches K3 and K4 are the switching control of remote sampling and proximal sampling. When K3 and K4 are closed, the converter works in the remote sampling mode. When K3 and K4 are disconnected, the converter works in the proximal sampling mode. K1 and K2 are power relays for the positive return line of the grid-connected controller output.

[0051] like Figure 5As shown, in order to solve the long life problem of voltage control, that is, to eliminate the voltage control accuracy deviation caused by time drift and temperature drift, in this embodiment, a step setting function based on bus instructions is added to the control target of the output voltage. After being processed by the grid-connected controller software (the software can be the prior art), the output is used as the voltage reference of the conversion circuit through digital-to-analog conversion. The specific implementation method is as follows: (a) sorting out the use conditions that affect the voltage accuracy, according to the single-machine on-orbit operating temperature, the simulation obtains that the operating temperature of the calculation device is 60°C, and the life of the single machine and the device is required to be more than 10 years; (b) the analog circuit (including Figure 4 and Figure 5 (c) A voltage injection instruction table is formulated according to the gear interval of 0.1V, and a voltage setting instruction is added to the command computer of the combined spacecraft system, and the voltage parameters can be adjusted by issuing commands from the ground; (d) The grid-connected controller software is designed to add a voltage setting instruction decoding function, receive the voltage injection instruction issued by the upstream computer, parse and output an 8-bit digital signal and a 1-bit low-level valid latch pulse signal, and give the output voltage value of the power component. (e) The power component converts the 8-bit digital signal into an analog voltage signal through a DA conversion circuit, and sends it to the converter control circuit as a voltage control reference. The control accuracy of the analog circuit is designed according to 0.02V to ensure the accuracy of the system control instruction.

[0052] By adjusting the reference of the voltage feedback loop, the output voltage needs to be adjustable in steps of no more than 0.1 V. The voltage output adjustable circuit converts the voltage bus command sent by the upstream computer into an 8-bit voltage reference signal that can be recognized by the power component by the intelligent component. According to the possible working range of the grid-connected voltage and with appropriate margin, the actual voltage grading capability is ΔV = (36-30) / 256 = 0.02 V.

[0053] In S500, the docking mechanism receives the adjusted signal and transmits it to the load through the floating disconnector. Figure 2 As shown, in this embodiment, the floating disconnect includes a passive floating disconnect provided on the docking mechanism and an active floating disconnect for connecting to a load. The load may be a visiting aircraft, and the active floating disconnect may be connected to the visiting aircraft through a grid-connected cable and a power distributor, thereby supplying power to the visiting aircraft through grid-connected power supply.

[0054] like Figure 5As shown, in this embodiment, due to the use of remote sampling, there is a higher technical risk compared to near-end sampling, and an additional EMC test link is required to ensure reliability. A scheme is adopted in which an expansion point module is set on the cable and a shielded cable is used to return the sampling signal, and an EMC test is performed by connecting the entire machine to the remote sampling cable to ensure the reliability of the sampling signal. The specific implementation process is as follows: (a) a remote sampling expansion point module device is added to the cable in the docking mechanism, and the expansion point module selects D436, selects 2 positive points and 2 negative points for power supply, and performs a 2-expansion-4 design to obtain two positive and two negative voltage acquisition signals to ensure the reliability of signal acquisition; (b) the voltage feedback signal is sent back to the grid-connected controller through the signal transmission cable in the docking mechanism and the transmission cable in the cabin. The cable adopts a twisted-pair shielded cable, and the shielding skin is well overlapped with the hull to ensure anti-interference capability; (c) at the same time The wire number and length of the cables at each connection point of the power supply cable should be consistent to reduce the impedance difference of each power supply cable and ensure the accuracy of the voltage at the sampling point. The cable impedance test is used to check that the cable resistance deviation should not exceed 2%; (d) An RC filter circuit is added to the sampling and conditioning circuit that receives the remote voltage signal to avoid output voltage fluctuations caused by interference introduced during long-line control: (e) Based on the near-end EMC test of a single machine, a method of connecting a remote sampling cable to the entire machine is proposed to perform EMC supplementary test verification. The test state is that the single machine provides constant voltage grid-connected power supply to the electronic load through the test cable. At this time, the voltage control is the working state of the remote sampling control. The test is carried out according to all items and requirements of the single machine EMC test, covering the startup, exit, steady-state power supply and load step process of the grid-connected power supply. The test result is passed, indicating that the EMC design meets the requirements.

[0055] The embodiment of the present invention sets the sampling feedback point of the grid-connected voltage control on the docking mechanism of the combined spacecraft, close to the floating disconnector and the load aircraft, and designs a high-precision voltage control circuit inside the grid-connected controller, and designs and implements a signal sampling and control method, which can achieve high-precision and long-life grid-connected voltage control, and can ensure that under the condition of an on-orbit life of more than 10 years, under the condition of large power fluctuations of the visiting aircraft load, the grid-connected power supply voltage output stability of the combined spacecraft is controlled within ±1.25%, and there is no need to add equipment or additional installation space on the basis of the existing spacecraft structure, and the original structure of the combined spacecraft is not affected, thereby achieving low cost.

[0056] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A grid-connected voltage control method for spacecraft rendezvous and docking, characterized in that: The grid-connected voltage control method comprises: S100, the combined spacecraft transforms the signal input from the busbar and outputs it to the docking mechanism through the grid-connected controller; S200, performing remote signal sampling on the docking mechanism; S300, feeding back the remote sampling signal to the grid-connected controller; S400, the grid-connected controller adjusts the voltage of the output signal according to the remote sampling signal and outputs it as the adjusted signal; S500, the docking mechanism receives the adjusted signal and transmits it to the load through a floating disconnector; An expansion point module is provided on the internal cable of the docking mechanism, and the expansion point module samples the remote signal and feeds it back to the grid-connected controller; In step S100, the signal input by the busbar is output to the docking mechanism through the grid-connected output cable of the combined spacecraft, and the docking mechanism includes a connector for connecting to the grid-connected output cable, the connector is connected to the expansion module, and the connector is also connected to the grid-connected controller through the signal transmission cable in the docking mechanism and the transmission cable in the cabin of the combined spacecraft; The grid-connected controller includes a high-precision voltage control circuit, which includes an operational amplifier conditioning circuit and a voltage divider circuit composed of five-level voltage divider resistors connected in series; In S400, the remote sampling signal clamps the total voltage of the second, third and fourth voltage-dividing resistors of the high-precision voltage control circuit and obtains an effective feedback voltage signal through the second, third and fourth voltage-dividing resistors, and then sends it to the converter control circuit through the operational amplifier conditioning circuit; Step S400 specifically includes: The accuracy deviation introduced by the sampling resistor, AD device time drift and temperature drift in the analog circuit and the voltage selection accuracy is calculated to obtain the maximum forward deviation and the maximum reverse deviation of the voltage; Determine the voltage adjustment gear interval according to the maximum forward deviation and the maximum reverse deviation of the voltage; Injecting the gear interval specified voltage into an instruction table, and adding a voltage setting instruction to a system instruction computer of the combined spacecraft; The grid-connected controller receives a voltage injection instruction from an upstream computer, parses and outputs an 8-bit digital signal and a 1-bit low-level valid latch pulse signal, and gives an output voltage value of a given power component; The power component converts the 8-bit digital signal into an analog voltage signal through a DA conversion circuit, and sends the analog voltage signal to the converter control circuit as a voltage control reference.

2. The grid-connected voltage control method for spacecraft rendezvous and docking according to claim 1, characterized in that: The expansion point module is D436.

3. The grid-connected voltage control method for spacecraft rendezvous and docking according to claim 1 or 2, characterized in that: The distance between the expansion point module and the floating disconnector is less than or equal to 0.2 meters.

4. The grid-connected voltage control method for spacecraft rendezvous and docking according to claim 3, characterized in that: The floating disconnect includes a passive floating disconnect arranged on the docking mechanism and an active floating disconnect used for connecting with the load.

5. The grid-connected voltage control method for spacecraft rendezvous and docking according to claim 1, characterized in that: The voltage adjustment gear interval is 0.02V.

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