Energy management method for direct-drive electric propulsion power supply system of spacecraft

Abstract

An energy management method for a direct-drive electric propulsion power supply system of a spacecraft belongs to the technical field of power supplies and comprises the following steps: determining a current power supply mode of the direct-drive electric propulsion power supply system according to a preset boundary condition; establishing a direct-drive electric propulsion power supply system optimization function under a preset constraint condition by taking the highest electric energy efficiency in the current power supply mode as an optimization target and taking the direct-current bus voltage as a control variable as an optimization function; and solving the optimization function of the direct-drive electric propulsion power supply system by using a golden section search algorithm to find an optimal direct-current bus voltage value. According to the working conditions such as the radiation intensity of the solar cell, the residual electric quantity of the storage battery, the power utilization requirements of the electric propeller and the load, the multi-mode switching and management strategy of the power supply system is designed, the voltage of the direct-current bus is controlled, the electric energy flow direction and load distribution are dynamically adjusted, and the energy utilization rate of direct-drive electric propulsion is comprehensively optimized.

Description

Technical Field

[0001] The invention relates to an energy management method for a spacecraft direct-drive electric propulsion power supply system, and belongs to the technical field of power supplies. Background Art

[0002] The solar cell-battery combined power supply has significant advantages such as high specific impulse, long life, and multi-point working mode. In the future, my country's deep space exploration missions will still be mainly powered by solar cells-batteries. Direct-drive electric propulsion uses solar cells to absorb light energy for power at perihelion, and the remaining electricity can be stored in batteries; when it reaches aphelion, the battery and solar panels jointly provide sufficient power. With the increase in detection distance (beyond 3AU), firstly, due to the limitations of the launch vehicle capabilities and the size of the spacecraft, high-power electric propulsion technology is required to support long-distance detection missions. Secondly, the solar radiation intensity decreases in inverse proportion to the square of the distance from the sun. The deep space exploration power supply system faces the problems of multi-operating point switching, high efficiency, and long endurance. Summary of the invention

[0003] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art, to provide an energy management method for a spacecraft direct-drive electric propulsion power supply system, to design a multi-mode switching and management strategy for the power supply system, to control the DC bus voltage, etc., to dynamically adjust the flow of electric energy and load distribution, and to comprehensively optimize the energy utilization rate of direct-drive electric propulsion.

[0004] The technical solution of the present invention is: an energy management method for a spacecraft direct-drive electric propulsion power supply system, comprising:

[0005] According to preset boundary conditions, determine the current power supply mode of the direct drive electric propulsion power supply system;

[0006] Taking the highest power efficiency under the current power supply mode as the optimization goal, the optimization function takes the DC bus voltage as the control variable, and establishes the optimization function of the direct-drive electric propulsion power supply system under the preset constraints;

[0007] The golden section search algorithm is used to solve the optimization function of the direct-drive electric propulsion power supply system and find the optimal DC bus voltage value.

[0008] Further, determining the current power supply mode of the direct drive electric propulsion power supply system includes:

[0009] If the maximum power that solar energy can provide under the current sunshine and temperature conditions is less than the current load power demand, and the battery SOC is greater than the first threshold value, the solar cell operates in the maximum power point MPPT mode, and the battery operates in the discharge mode, and the discharge cut-off condition is that the SOC drops to the first threshold value;

[0010] If the maximum power that solar energy can provide under the current sunshine and temperature conditions is greater than the current load power demand, and the battery SOC is less than the second threshold value, the solar cell operates in the maximum power point MPPT mode, and the battery operates in the charging mode, and the charging cut-off condition is that the SOC rises to the second threshold value;

[0011] If the instantaneous power provided by solar energy under the current sunshine and temperature conditions is greater than the current load power demand, and the battery SOC is less than the third threshold value, the solar cell operates in the constant voltage mode, and the battery operates in the charging mode until the SOC reaches the third threshold value, and then stops, and only the solar cell is used for power supply;

[0012] If the instantaneous power provided by solar energy under the current sunshine and temperature conditions is less than the current load power demand, and the battery SOC is greater than the second threshold value, the solar cell operates in constant voltage mode, and the battery operates in discharge mode to the fourth threshold value, and it is determined again whether the solar cell can enter the maximum power point MPPT mode.

[0013] Furthermore, the first threshold, the second threshold, the third threshold and the fourth threshold are 20%, 90%, 98% and 80% respectively.

[0014] Furthermore, the preset constraints include:

[0015] Electric power balance constraint: at any time, the power supplied is balanced with the power consumed by the load;

[0016] Battery capacity constraint: the battery SOC should be greater than the first threshold value and less than the third threshold value;

[0017] Charge and discharge power constraints: the battery charge and discharge power cannot exceed the maximum power;

[0018] The maximum power consumption of the load must not exceed the maximum power.

[0019] DC bus voltage regulation constraints: the electrical equipment on the DC bus cannot exceed the range of maximum and minimum operating voltages.

[0020] Furthermore, the use of the golden section search algorithm to solve the optimization function of the direct drive electric propulsion power supply system includes:

[0021] Step 1: After determining the current power supply mode, in the DC bus voltage range [U a ,U b ] Select two points U c =U a +(1-γ)·h and U d =U a +γ·h, where and h=U b -U a ;

[0022] Step 2: If U c and U d If the difference between the values ​​of the electric energy efficiency of the two points is less than the first preset threshold and the width of the interval is less than the second preset threshold, the loop is stopped and U dc-best =U c or U dc-best =U d ;

[0023] Step 3: If U c The energy efficiency is less than U d The energy efficiency of c Let U be the new lower bound of the interval. d is the new upper bound of the interval; go to step 1.

[0024] Furthermore, the electric energy efficiency is Among them, P PV is the power provided by the solar cell at the current moment, which is converted into the DC bus voltage U by the solar DC / DC converter. dc Establish contact; BAT is the power of the battery at the current moment, which is converted to the DC bus voltage U by the battery bidirectional DC / DC converter. dc Establish contact; loss is the power loss at the current moment, which is connected to the DC bus voltage U through the distribution line layout. dc Establish contact; IN It is the total energy input of direct drive electric propulsion at the current moment.

[0025] An energy management system for a spacecraft direct-drive electric propulsion power supply system, comprising:

[0026] The first module determines the current power supply mode of the direct drive electric propulsion power supply system according to preset boundary conditions;

[0027] In the second module, the optimization goal is to maximize the power efficiency under the current power supply mode. The optimization function uses the DC bus voltage as the control variable and establishes the optimization function of the direct-drive electric propulsion power supply system under the preset constraints.

[0028] In the third module, the golden section search algorithm is used to solve the optimization function of the direct-drive electric propulsion power supply system to find the optimal DC bus voltage value.

[0029] Further, determining the current power supply mode of the direct drive electric propulsion power supply system includes:

[0030] If the maximum power that solar energy can provide under the current sunshine and temperature conditions is less than the current load power demand, and the battery SOC is greater than the first threshold value, the solar cell operates in the maximum power point MPPT mode, and the battery operates in the discharge mode, and the discharge cut-off condition is that the SOC drops to the first threshold value;

[0031] If the maximum power that solar energy can provide under the current sunshine and temperature conditions is greater than the current load power demand, and the battery SOC is less than the second threshold value, the solar cell operates in the maximum power point MPPT mode, and the battery operates in the charging mode, and the charging cut-off condition is that the SOC rises to the second threshold value;

[0032] If the instantaneous power provided by solar energy under the current sunshine and temperature conditions is greater than the current load power demand, and the battery SOC is less than the third threshold value, the solar cell operates in the constant voltage mode, and the battery operates in the charging mode until the SOC reaches the third threshold value, and then stops, and only the solar cell is used for power supply;

[0033] If the instantaneous power provided by solar energy under the current sunshine and temperature conditions is less than the current load power demand, and the battery SOC is greater than the second threshold value, the solar cell operates in the constant voltage mode, and the battery operates in the discharge mode to the fourth threshold value, and it is determined again whether the solar cell can enter the maximum power point MPPT mode;

[0034] Further, the first threshold value, the second threshold value, the third threshold value, and the fourth threshold value are 20%, 90%, 98%, and 80% respectively;

[0035] Furthermore, the preset constraints include:

[0036] Electric power balance constraint: at any time, the power supplied is balanced with the power consumed by the load;

[0037] Battery capacity constraint: the battery SOC should be greater than the first threshold value and less than the third threshold value;

[0038] Charge and discharge power constraints: the battery charge and discharge power cannot exceed the maximum power;

[0039] The maximum power consumption of the load must not exceed the maximum power.

[0040] DC bus voltage regulation constraints: the electrical equipment on the DC bus cannot exceed the range of maximum and minimum operating voltages;

[0041] Furthermore, the use of the golden section search algorithm to solve the optimization function of the direct drive electric propulsion power supply system includes:

[0042] Step 1: After determining the current power supply mode, in the DC bus voltage range [Ua ,U b ] Select two points U c =U a +(1-γ)·h and U d =U a +γ·h, where and h=U b -U a ;

[0043] Step 2: If U c and U d If the difference between the values ​​of the electric energy efficiency of the two points is less than the first preset threshold and the width of the interval is less than the second preset threshold, the loop is stopped and U dc-best =U c or U dc-best =U d ;

[0044] Step 3: If U c The energy efficiency is less than U d The energy efficiency of c Let U be the new lower bound of the interval. d is the new upper bound of the interval; go to step 1;

[0045] The electrical energy efficiency is Among them, P PV is the power provided by the solar cell at the current moment, which is converted into the DC bus voltage U by the solar DC / DC converter. dc Establish contact; BAT is the power of the battery at the current moment, which is converted to the DC bus voltage U by the battery bidirectional DC / DC converter. dc Establish contact; loss is the power loss at the current moment, which is connected to the DC bus voltage U through the distribution line layout. dc Establish contact; IN It is the total energy input of direct drive electric propulsion at the current moment.

[0046] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of an energy management method for a spacecraft direct-drive electric propulsion power supply system.

[0047] An energy management device for a spacecraft direct-drive electric propulsion power supply system comprises a memory, a processor and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of an energy management method for a spacecraft direct-drive electric propulsion power supply system are implemented.

[0048] The advantages of the present invention compared with the prior art are:

[0049] (1) The present invention determines the working mode by evaluating the radiation intensity of the solar cell, the remaining power of the battery, the power demand of the electric propulsion device, etc., controls the DC bus voltage and the direction of electric energy flow with the highest power efficiency under the current power supply mode, realizes dynamic management of electric energy, and can improve the efficiency of the direct drive electric propulsion power supply system;

[0050] (2) The present invention uses the golden section search algorithm to find the optimal DC bus voltage value, thereby dynamically adjusting the power flow direction and load distribution. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0052] Figure 1 This is a structural diagram of the direct-drive electric propulsion power supply system of the present invention. DETAILED DESCRIPTION

[0053] In order to better understand the above technical scheme, the technical scheme of the present invention is described in detail below through the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical scheme of the present invention, rather than limitations on the technical scheme of the present invention. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.

[0054] The following is a further detailed description of an energy management method for a spacecraft direct-drive electric propulsion power supply system provided by an embodiment of the present invention in conjunction with the accompanying drawings of the specification. The specific implementation method may include:

[0055] Firstly, according to the boundary conditions, the current power supply mode of the direct-drive electric propulsion power system is determined;

[0056] Secondly, when the power supply mode is determined, the optimization goal is to maximize the power efficiency under the current power supply mode, and the optimization function of the direct-drive electric propulsion power supply system is established. The optimization function uses the DC bus voltage as the control variable.

[0057] Then the golden section search algorithm is used to find the optimal DC bus voltage value.

[0058] In one possible implementation, the direct-drive electric propulsion power supply system described in the present invention includes: solar cells, batteries, solar DC / DC converters, battery bidirectional DC / DC converters, DC bus voltage controllers, solar cell controllers, energy controllers, electric propulsion power supplies and loads.

[0059] Furthermore, the energy management method of a direct-drive electric propulsion power supply system described in the present invention includes boundary conditions, the boundary conditions, the difference between the power that can be provided by the solar cell and the load power consumption under the current sunshine and temperature conditions, and the state of charge (SOC) threshold value of the battery.

[0060] In one possible implementation, the energy management method of a direct-drive electric propulsion power supply system described in the present invention includes a power supply mode, and the power supply mode includes: a maximum power point (MPPT) mode and a constant voltage mode of a solar cell, and a charging mode and a discharging mode of a battery.

[0061] Furthermore, an energy management method for a direct-drive electric propulsion power supply system described in the present invention includes an optimization function of the direct-drive electric propulsion power supply system, and the optimization function of the direct-drive electric propulsion power supply system includes: taking the highest electric energy efficiency under the current power supply mode as the optimization target, taking electric power balance, battery capacity, charging and discharging power, maximum load power consumption, DC bus voltage range, etc. as constraints, and taking the DC bus voltage as the control variable.

[0062] Furthermore, the energy management method of a direct-drive electric propulsion power supply system described in the present invention includes a golden section search algorithm, and the deep golden section search algorithm includes:

[0063] Step 1: After the mode is determined, in the DC bus voltage range [U a ,U b ] Select two points U c =U a +(1-γ)·h and U d =U a +γ·h, where and h=U b -U a .

[0064] Step 2: If U c and U d The values ​​of the energy efficiency at the two points are almost equal [i.e. |f(U c )-f(U d )|<value 1 set by the algorithm] and the width of the interval is small enough (i.e. h<value 2 set by the algorithm), then stop exiting the loop and set U dc-best =U c or U dc-best =U d .

[0065] Step 3: If f(U c ) <f(U d ), let U c Let U be the new lower bound of the interval. d is the new upper bound of the interval. Then, go to step 1.

[0066] In the solution provided in the embodiment of the present invention, an energy management method for a direct-drive electric propulsion power supply system is provided. The structure of the direct-drive electric propulsion power supply system is as follows: Figure 1 As shown. First, according to the boundary conditions, determine the direct drive electric propulsion power supply mode. Specifically, if the maximum power that solar energy can provide under the current sunshine and temperature conditions is less than the current load power demand, and the battery SOC is greater than the first threshold value (such as 20%), the solar cell operates in the maximum power point (MPPT) mode, and the battery operates in the discharge mode. The discharge cut-off condition is that the SOC drops to the first threshold value (such as 20%); if the maximum power that solar energy can provide under the current sunshine and temperature conditions is greater than the current load power demand, and the battery SOC is less than the second threshold value (such as 90%), the solar cell operates in the maximum power point (MPPT) mode, and the battery operates in the charging mode. The charging cut-off condition is that the SOC rises to the second threshold value. value; if the instantaneous power provided by solar energy under the current sunshine and temperature conditions is greater than the current load power demand, and the battery SOC is less than the third threshold value (the battery is close to saturation, such as 98%), the solar cell operates in constant voltage mode, and the battery operates in charging mode until the SOC reaches the third threshold value and stops, and only the solar cell is used for power supply; if the instantaneous power provided by solar energy under the current sunshine and temperature conditions is less than the current load power demand, and the battery SOC is greater than the second threshold value, the solar cell operates in constant voltage mode, and the battery operates in discharge mode to the fourth threshold value (such as 80%), and it is judged again whether the solar cell can enter the MPPT mode.

[0067] Secondly, when the mode is determined, the optimization function of the direct-drive electric propulsion power system is established with the highest power efficiency in this mode as the optimization goal, power balance, battery capacity, charging and discharging power, maximum load power, DC bus voltage range, etc. as constraints, and DC bus voltage as the control variable.

[0068] The electrical energy efficiency is defined as: Where P load is the power consumption of loads such as electric propulsion at the current moment; P PV is the power provided by the solar cell at the current moment, which is converted into the DC bus voltage U by the solar DC / DC converter. dc Establish contact; BATis the power of the battery at the current moment, which is converted to the DC bus voltage U by the battery bidirectional DC / DC converter. dc Establish contact; loss is the power loss at the current moment, which is connected to the DC bus voltage U through the distribution line layout. dc Establish contact; IN is the total energy input of direct drive electric propulsion at the current moment. Therefore, the power efficiency and DC bus voltage U dc Establish a link function relationship.

[0069] The electric power balance constraint means that at any time, the power supplied and the power consumed by the load need to be balanced.

[0070] The battery capacity constraint means that the SOC of the battery should be greater than a first threshold value (such as 20%) and less than a third threshold value (such as 98%).

[0071] The charge and discharge power constraint means that both the battery charge and discharge have maximum power requirements. If the maximum power is exceeded, the battery and the distribution line will be damaged.

[0072] The maximum power constraint of load power consumption means that all load power consumption has a maximum power requirement, and exceeding the maximum power will damage the equipment and distribution lines.

[0073] The DC bus voltage regulation constraint means that the electrical equipment on the DC bus has maximum and minimum operating voltage requirements. If the maximum voltage is exceeded, the equipment will be damaged, and if the voltage is lower than the minimum voltage, the equipment will not work.

[0074] Then, the golden section search algorithm is used to find the optimal DC bus voltage value. Usually, the DC bus voltage of direct drive electric propulsion has a certain adjustment range, such as (60V~120V). Golden section search is an algorithm used to find the extreme value of a function within a specified interval, which is suitable for the problem to be solved by this patent. The algorithm steps are as follows:

[0075] Step 1: After the mode is determined, in the DC bus voltage range [U a ,U b ] Select two points U c =U a +(1-γ)·h and U c =U a +(1-γ)·h, where U c =U a +(1-γ)·h and U c =U a +(1-γ)·h.

[0076] Step 2: If U c and U dThe values ​​of the energy efficiency at the two points are almost equal [i.e. |f(U c )-f(U d )|<value 1 set by the algorithm] and the width of the interval is small enough (i.e. h<value 2 set by the algorithm), then stop exiting the loop and set U dc-best =U c or U dc-best =U d .

[0077] Step 3: If f(U c ) <f(U d ), let U c Let U be the new lower bound of the interval. d is the new upper bound of the interval. Then, go to step 1.

[0078] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0079] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

[0080] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. An energy management method for a spacecraft direct-drive electric propulsion power supply system, characterized in that: include: According to preset boundary conditions, determine the current power supply mode of the direct drive electric propulsion power supply system; Taking the highest power efficiency under the current power supply mode as the optimization goal, the optimization function takes the DC bus voltage as the control variable, and establishes the optimization function of the direct-drive electric propulsion power supply system under the preset constraints; The golden section search algorithm is used to solve the optimization function of the direct-drive electric propulsion power supply system and find the optimal DC bus voltage value.

2. The energy management method of a spacecraft direct-drive electric propulsion power supply system according to claim 1, characterized in that: Determining the current power supply mode of the direct drive electric propulsion power supply system includes: If the maximum power that solar energy can provide under the current sunshine and temperature conditions is less than the current load power demand, and the battery SOC is greater than the first threshold value, the solar cell operates in the maximum power point MPPT mode, and the battery operates in the discharge mode, and the discharge cut-off condition is that the SOC drops to the first threshold value; If the maximum power that solar energy can provide under the current sunshine and temperature conditions is greater than the current load power demand, and the battery SOC is less than the second threshold value, the solar cell operates in the maximum power point MPPT mode, and the battery operates in the charging mode, and the charging cut-off condition is that the SOC rises to the second threshold value; If the instantaneous power provided by solar energy under the current sunshine and temperature conditions is greater than the current load power demand, and the battery SOC is less than the third threshold value, the solar cell operates in the constant voltage mode, and the battery operates in the charging mode until the SOC reaches the third threshold value, and then stops, and only the solar cell is used for power supply; If the instantaneous power provided by solar energy under the current sunshine and temperature conditions is less than the current load power demand, and the battery SOC is greater than the second threshold value, the solar cell operates in constant voltage mode, and the battery operates in discharge mode to the fourth threshold value, and it is determined again whether the solar cell can enter the maximum power point MPPT mode.

3. The energy management method of a spacecraft direct-drive electric propulsion power supply system according to claim 2, characterized in that: The first threshold, the second threshold, the third threshold and the fourth threshold are 20%, 90%, 98% and 80% respectively.

4. The energy management method of a spacecraft direct-drive electric propulsion power supply system according to claim 1, characterized in that: The preset constraints include: Electric power balance constraint: at any time, the power supplied is balanced with the power consumed by the load; Battery capacity constraint: the battery SOC should be greater than the first threshold value and less than the third threshold value; Charge and discharge power constraints: the battery charge and discharge power cannot exceed the maximum power; The maximum power consumption of the load must not exceed the maximum power. DC bus voltage regulation constraints: the electrical equipment on the DC bus cannot exceed the range of maximum and minimum operating voltages.

5. The energy management method of a spacecraft direct-drive electric propulsion power supply system according to claim 1, characterized in that: The method of solving the optimization function of the direct-drive electric propulsion power supply system by using the golden section search algorithm includes: Step 1: After determining the current power supply mode, in the DC bus voltage range [U a ,U b ] Select two points U c =U a +(1-γ)·h and U d =U a +γ·h, where and h=U b -U a ; Step 2: If U c and U d If the difference between the values ​​of the electric energy efficiency of the two points is less than the first preset threshold and the width of the interval is less than the second preset threshold, the loop is stopped and U dc-best =U c or U dc-best =U d ; Step 3: If U c The energy efficiency is less than U d The energy efficiency of c Let U be the new lower bound of the interval. d is the new upper bound of the interval; go to step 1.

6. The energy management method of a spacecraft direct-drive electric propulsion power supply system according to claim 5, characterized in that: The electrical energy efficiency is Among them, P PV is the power provided by the solar cell at the current moment, which is converted into the DC bus voltage U by the solar DC / DC converter. dc Establish contact; BAT is the power of the battery at the current moment, which is converted to the DC bus voltage U by the battery bidirectional DC / DC converter. dc Establish contact; loss is the power loss at the current moment, which is connected to the DC bus voltage U through the distribution line layout. dc Establish contact; IN It is the total energy input of direct drive electric propulsion at the current moment.

7. An energy management system for a spacecraft direct-drive electric propulsion power supply system, characterized in that: include: The first module determines the current power supply mode of the direct drive electric propulsion power supply system according to preset boundary conditions; In the second module, the optimization goal is to maximize the power efficiency under the current power supply mode. The optimization function uses the DC bus voltage as the control variable and establishes the optimization function of the direct-drive electric propulsion power supply system under the preset constraints. In the third module, the golden section search algorithm is used to solve the optimization function of the direct-drive electric propulsion power supply system to find the optimal DC bus voltage value.

8. The energy management system of a spacecraft direct-drive electric propulsion power supply system according to claim 7, characterized in that: Determining the current power supply mode of the direct drive electric propulsion power supply system includes: If the maximum power that solar energy can provide under the current sunshine and temperature conditions is less than the current load power demand, and the battery SOC is greater than the first threshold value, the solar cell operates in the maximum power point MPPT mode, and the battery operates in the discharge mode, and the discharge cut-off condition is that the SOC drops to the first threshold value; If the maximum power that solar energy can provide under the current sunshine and temperature conditions is greater than the current load power demand, and the battery SOC is less than the second threshold value, the solar cell operates in the maximum power point MPPT mode, and the battery operates in the charging mode, and the charging cut-off condition is that the SOC rises to the second threshold value; If the instantaneous power provided by solar energy under the current sunshine and temperature conditions is greater than the current load power demand, and the battery SOC is less than the third threshold value, the solar cell operates in the constant voltage mode, and the battery operates in the charging mode until the SOC reaches the third threshold value, and then stops, and only the solar cell is used for power supply; If the instantaneous power provided by solar energy under the current sunshine and temperature conditions is less than the current load power demand, and the battery SOC is greater than the second threshold value, the solar cell operates in the constant voltage mode, and the battery operates in the discharge mode to the fourth threshold value, and it is determined again whether the solar cell can enter the maximum power point MPPT mode; The first threshold value, the second threshold value, the third threshold value, and the fourth threshold value are 20%, 90%, 98%, and 80% respectively; The preset constraints include: Electric power balance constraint: at any time, the power supplied is balanced with the power consumed by the load; Battery capacity constraint: the battery SOC should be greater than the first threshold value and less than the third threshold value; Charge and discharge power constraints: the battery charge and discharge power cannot exceed the maximum power; The maximum power consumption of the load must not exceed the maximum power. DC bus voltage regulation constraints: the electrical equipment on the DC bus cannot exceed the range of maximum and minimum operating voltages; The method of solving the optimization function of the direct-drive electric propulsion power supply system by using the golden section search algorithm includes: Step 1: After determining the current power supply mode, in the DC bus voltage range [U a ,U b ] Select two points U c =U a +(1-γ)·h and U d =U a +γ·h, where and h=U b -U a ; Step 2: If U c and U d If the difference between the values ​​of the electric energy efficiency of the two points is less than the first preset threshold and the width of the interval is less than the second preset threshold, the loop is stopped and U dc-best =U c or U dc-best =U d ; Step 3: If U c The energy efficiency is less than U d The energy efficiency of c Let U be the new lower bound of the interval. d is the new upper bound of the interval; go to step 1; The electrical energy efficiency is Among them, P PV is the power provided by the solar cell at the current moment, which is converted into the DC bus voltage U by the solar DC / DC converter. dc Establish contact; BAT is the power of the battery at the current moment, which is converted to the DC bus voltage U by the battery bidirectional DC / DC converter. dc Establish contact; loss is the power loss at the current moment, which is connected to the DC bus voltage U through the distribution line layout. dc Establish contact; IN It is the total energy input of direct drive electric propulsion at the current moment.

9. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

10. An energy management device for a spacecraft direct-drive electric propulsion power supply system, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 6 are implemented.

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