Spacecraft lithium battery on-orbit efficient autonomous management and protection system

Abstract

The application provides a spacecraft lithium battery on-orbit efficient autonomous management and protection system, which comprises a lithium battery charging and discharging adjusting device, a plurality of independent lithium battery charging and discharging adjusting circuits, two groups of BCDRiA and BCDRiB, i can be flexibly configured according to power requirements, a bypass switch used for switching a lithium battery monomer or a parallel assembly to a bypass device when the voltage range of the lithium battery monomer or the parallel assembly exceeds a preset threshold range, a central computer in communication with the lithium battery charging and discharging adjusting device, collecting charging and discharging adjustment related telemetry, performing lithium battery on-orbit charging and discharging autonomous management, and performing fault processing and protection when monitoring abnormal telemetry. The application can solve the problems in the prior art that lithium battery on-orbit charging and discharging management depends on energy software, the scheme is complex, the reliability is low, and the safety is insufficient, and improve the lithium battery on-orbit operation and the energy safety of the whole satellite.

Description

Technical Field

[0001] This invention is applied to the intelligent autonomous management of spacecraft, and in particular relates to the on-orbit autonomous management and protection system for spacecraft lithium batteries. Background Technology

[0002] Lithium batteries are currently widely used in spacecraft. In order to ensure the long-term operation of lithium-ion batteries in orbit, it is necessary to carry out on-orbit autonomous management and protection design for lithium batteries during long periods of sunlight and shadow.

[0003] Traditional on-orbit charge / discharge management solutions for lithium batteries typically rely on power software to control the battery voltage. During extended periods of inactivity, supplementary charging is also handled by the power software, which is quite complex. Subsequently, to simplify the software, hardware was used to control the battery voltage. However, the software state transitions between charge and discharge, including supplementary charging during long periods of inactivity, still rely on power software. Summary of the Invention

[0004] To address the issues of existing technologies where on-orbit charging and discharging management of lithium batteries relies on energy software, resulting in complex schemes, low reliability, and insufficient safety, this invention proposes a spacecraft lithium battery on-orbit efficient autonomous management and protection system. This system improves the on-orbit operation of lithium batteries and the energy safety of the entire satellite, further optimizes the requirements of autonomous on-orbit charging and discharging management of lithium batteries on the software resources of the entire satellite, and simultaneously achieves overcharge and over-discharge protection for lithium batteries.

[0005] To achieve the above objectives, the present invention adopts the following solution:

[0006] This invention proposes an efficient on-orbit autonomous management and protection system for spacecraft lithium batteries, comprising:

[0007] The lithium battery charge and discharge regulation device includes several independent lithium battery charge and discharge regulation circuits (BCDRs), which are divided into two groups, A and B, to charge two groups of lithium-ion battery packs respectively. Each independent BCDR is named BCDRiA or BCDRiB according to the group, where i is the number of the BCDR in the group, and the maximum value of i can be flexibly configured according to the power requirements.

[0008] Bypass switch: When the voltage range of a certain lithium battery cell or parallel component exceeds the preset threshold range, the bypass switch will bypass the battery cell or parallel component.

[0009] The central computer communicates with the lithium battery charge and discharge regulation device via the 1553B bus, collects relevant telemetry data such as battery voltage, battery charging current, battery discharging current, and bus voltage amplification signal, and performs autonomous on-orbit charge and discharge management of the lithium battery. If telemetry anomalies are detected, fault handling and protection are performed.

[0010] Furthermore, the spacecraft lithium battery on-orbit high-efficiency autonomous management and protection system is mainly based on hardware circuits. In the lithium battery charging and discharging regulation device, hardware circuits are used to realize constant current and voltage limiting control of the lithium battery. That is, in the lithium battery charging and discharging regulation device, the lithium battery is charged at a constant current through a current closed-loop hardware circuit. After reaching the voltage limit value, the lithium battery is charged at a constant voltage through a voltage closed-loop hardware circuit until the charging current is reduced to 0. At the same time, the energy software in the central computer autonomously determines whether it is in a state of illumination or Earth-Moon shadow, and switches between the illumination season and the Earth (Moon) shadow season according to the judgment result.

[0011] Furthermore, in the strategy for autonomously determining the illumination / earth (moon) shadow flag, the switching condition for illumination to earth (moon) shadow is that the central computer energy software receives three consecutive frames of telemetry data that satisfy: the battery discharge current is greater than the first preset threshold; the bus error amplification signal in the lithium battery charge and discharge regulation device is less than the second preset threshold; after the conditions are met, the central computer energy software sends a battery pack constant voltage charging voltage setting command and a battery pack constant voltage charging current setting command to the lithium battery charge and discharge regulation device, adjusts the command code value to the earth shadow season threshold, and at the same time, sets the illumination / earth (moon) shadow flag to earth (moon) shadow.

[0012] Furthermore, in the strategy for autonomously determining the illumination / earth (moon) shadow marker, the switching condition for the earth (moon) shadow to illumination is that the central computer's energy software continuously... LR The telemetry data meets the following conditions: the battery discharge current is less than the third preset threshold; the bus error amplification signal in the lithium battery charge and discharge regulation device is greater than the fourth preset threshold; after the conditions are met, the central computer energy software sends the battery pack constant voltage charging voltage setting instruction and the battery pack constant voltage charging current setting instruction to the lithium battery charge and discharge regulation device, adjusts the instruction code value to the sunshine season threshold, and at the same time sets the sunshine / ground (moon) shadow flag to sunshine.

[0013] Among them, T LR It is generally set to 48 hours (geosynchronous orbit), but can be adjusted according to the actual situation of satellite illumination season and Earth shadow season.

[0014] Furthermore, the strategy for autonomously determining the illumination / ground (moon) shadow flag is characterized in that, after software initialization, the illumination / ground (moon) shadow flag defaults to illumination; when the illumination / ground (moon) shadow flag is illumination, the software does not perform the conversion condition detection for switching from ground (moon) shadow to illumination, but detects the conversion condition criteria for switching from illumination to ground (moon) shadow in real time; when the illumination / ground (moon) shadow flag is illumination, the software does not perform the conversion condition criteria detection for switching from illumination to ground (moon) shadow, but detects the conversion condition for switching from ground (moon) shadow to illumination in real time.

[0015] Furthermore, the central computer energy software can realize the software-side protection of the battery pack for overcharging, including: accumulating the available status indicators of individual cells in real time through the central computer energy software, calculating the total number of unavailable status indicators in the battery pack, and calculating the overcharge judgment voltage value of the battery pack through the first calculation unit based on the given upper limit value of the individual cell voltage, the given voltage error value of the battery overvoltage, and the aforementioned number of unavailable status indicators. If three consecutive telemetry frames meet the condition that the battery telemetry voltage value exceeds the overcharge judgment voltage value of the battery pack, a charging prohibition command is sent to all lithium battery charging and discharging regulation circuits of the corresponding battery pack to stop charging the overcharged battery pack, and at the same time, a corresponding battery pack software overcharge protection alarm telemetry is generated.

[0016] Furthermore, after sending a charging prohibition command to the lithium battery charge / discharge regulation circuit corresponding to the overcharged battery pack, the system checks whether the charging current of the overcharged battery pack is zero. If yes, the charging prohibition command is not sent again, and the software function continues. If no, the corresponding charging prohibition command for the overcharged battery pack is sent again, and the system continues to check whether the charging current of the overcharged battery pack is zero. A single command can be sent a maximum of 3 times. If the charging current of the overcharged battery pack is still not zero after the third command is sent, a battery pack charging prohibition function fault alarm flag is generated remotely, and the overcharge protection criterion detection and charging prohibition command sending will no longer be carried out for the overcharged battery pack.

[0017] Furthermore, the software autonomously judges the overcharge protection of the battery pack: when the voltage of the overcharged battery pack recovers to below 95% of the overcharge protection voltage value set by the software, the software overcharge protection alarm flag is released, and at the same time, a charging enable command is sent to the lithium battery charging and discharging regulation circuit corresponding to the original overcharged battery pack.

[0018] Furthermore, the battery pack over-discharge protection is implemented through the energy software of the central computer. This includes: the central computer's energy software collecting the Earth and Moon shadow markers and battery voltage values, which are then processed by the second calculation unit to calculate and update the state of charge and depth of discharge of the two battery packs in real time; the energy software collecting the battery pack discharge current and the bus error amplification signal in the lithium battery charge and discharge regulation device, and accumulating the discharge time of each of the two battery packs in real time with a single software control cycle (determined according to computer capabilities, such as 500 milliseconds); and determining if the calculated state of charge of the battery pack is lower than the fifth preset threshold for three consecutive frames, generating a remotely measured battery pack discharge fault alarm flag.

[0019] Furthermore, the method for calculating the battery discharge time satisfies the following conditions:

[0020] When the energy software receives three consecutive frames of telemetry data that meet the following conditions: the battery discharge current is greater than the first preset threshold and the bus error amplification signal in the lithium battery charge and discharge regulation device is less than the second preset threshold, the power management software will start accumulating the battery discharge time in steps of a single software control cycle.

[0021] When the energy software receives three consecutive frames of telemetry data that meet the following conditions: the battery discharge current is less than the third preset threshold and the bus error amplification signal in the lithium battery charge and discharge regulation device is greater than the fourth preset threshold, the battery discharge time accumulation is stopped.

[0022] Furthermore, when generating a battery pack discharge fault alarm sign telemetry, the payload power-off command is first sent in order of payload importance from low to high, and necessary (to maintain the lower limit of the operating temperature of the payload compartment instruments and equipment) payload compartment alternative heater turn-on command and other non-essential automatic control heater power-off command are sent.

[0023] After sequentially sending the payload power-off command and other non-essential automatic heater power-off commands, immediately check whether the battery pack discharge current is less than (P) for three consecutive telemetry physical quantities. SOC -0.2)C / (1.2-T D / 3600); where C is the battery pack capacity, P SOC For calculating the state of charge of the battery pack, T D If the calculated battery discharge time is specified, then stop sending power-off commands; otherwise, continue sending power-off commands sequentially.

[0024] The beneficial effects of this invention are: it proposes a spacecraft lithium battery on-orbit high-efficiency autonomous management and protection system scheme based on hardware circuits and autonomous energy software, which further optimizes the requirements of the whole satellite software resources for autonomous on-orbit charging and discharging management of lithium batteries, while ensuring the on-orbit operation safety of lithium batteries and the energy security of the whole satellite. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the on-orbit high-efficiency autonomous management and protection system architecture for lithium batteries of the present invention;

[0026] Figure 2 This is the autonomous determination strategy for lighting / ground (moon) shadow markers in the embodiments of the present invention;

[0027] Figure 3 This is the battery pack overcharge judgment and handling strategy in the embodiments of the present invention;

[0028] Figure 4 This is the battery pack over-discharge judgment and handling strategy in the embodiments of the present invention. Detailed Implementation

[0029] This chapter describes the specific implementation methods.

[0030] (1) As Figure 1 As shown, a spacecraft lithium battery on-orbit high-efficiency autonomous management and protection system is characterized by comprising: a lithium battery charge and discharge regulation device (containing several independent lithium battery charge and discharge regulation circuits, divided into two groups BCDRiA and BCDRiB, i = 1 to 8, corresponding to battery group A and battery group B respectively), a bypass switch (a device that bypasses a lithium battery cell or parallel component when the voltage range of a certain lithium battery cell or parallel component exceeds a preset threshold range, corresponding to the lithium battery cell or parallel component), and a central computer (communicating with the lithium battery charge and discharge regulation device via a 1553B bus, collecting telemetry related to charge and discharge regulation, performing autonomous on-orbit charge and discharge management of the lithium battery, and performing fault handling and protection if telemetry anomalies are detected).

[0031] (2) A spacecraft lithium battery on-orbit high-efficiency autonomous management and protection system, characterized in that the lithium battery on-orbit high-efficiency autonomous charging and discharging management system is mainly based on hardware circuits. In the lithium battery charging and discharging adjustment device, hardware circuits are used to realize the constant current and voltage limiting control of the lithium battery. At the same time, the energy software in the central computer autonomously judges the light / earth (moon) shadow flags, thereby realizing the switching between the light season and the earth shadow season.

[0032] (3) Figure 2 As shown, the strategy for autonomously determining the illumination / earth (moon) shadow markers is as follows:

[0033] After software initialization, the illumination / ground (moon) shadow flag defaults to illumination; when the illumination / ground (moon) shadow flag is illumination, the software does not perform the conversion condition (criterion 2) detection for switching from ground (moon) shadow to illumination, but detects the conversion condition (criterion 1) for switching from illumination to ground (moon) shadow in real time; when the illumination / ground (moon) shadow flag is illumination, the software does not perform the conversion condition (criterion 1) detection for switching from illumination to ground (moon) shadow, but detects the conversion condition (criterion 2) for switching from ground (moon) shadow to illumination in real time.

[0034] The switching condition for the illumination to Earth (Moon) shadow is that the central computer energy software continuously provides three frames of telemetry data that meet criterion 1: the battery discharge current is greater than the first preset threshold (2.8); and the bus error amplification signal in the lithium battery charge and discharge regulation device is less than the second preset threshold (10.8).

[0035] Once the conditions are met, the central computer's energy software sends a constant voltage charging voltage setting command (initial value 7.5) and a constant voltage charging current setting command (initial value 84) to the lithium battery charging and discharging regulation device. Simultaneously, it sets the light / ground (moon) shadow flag to / ground (moon) shadow (Z). M =1).

[0036] The condition for switching from Earth (Moon) shadow to illumination is that the central computer energy software continuously T LR The telemetry data meet the following conditions: the battery discharge current is less than the third preset threshold (2.5); the bus error amplification signal in the lithium battery charge and discharge regulation device is greater than the fourth preset threshold (11.5).

[0037] Once the conditions are met, the central computer's energy software sends a constant-voltage charging voltage setting command (initial value 80) and a constant-voltage charging current setting command (initial value 1.5) to the lithium battery charging and discharging regulation device. Simultaneously, it sets the illumination / ground (moon) shadow flag to illumination (Z). M =0).

[0038] (4) Figure 3 As shown, the overcharge detection and handling strategy for the battery pack is as follows:

[0039] Step 1: Individual cell availability status indicator and cumulative status

[0040] In the initial state of the energy software, all individual cells are in an available state, and the total number of available state flags in both battery banks is N. T .

[0041] A bypass faulty individual battery is activated by a remote control command sent from the ground. Simultaneously, a command is sent from the ground to set the available status flag of that battery string to unavailable. The total number of unavailable status flags in both battery banks (N) is calculated cumulatively. FA and N FB ).

[0042] Step 2: Energy Calculation - Overcharge Judgment Voltage Value of Two Battery Banks

[0043] V OCPA =(N T -N FA )×V CELLF +Ve

[0044] V OCPB =(N T -N FB )×V CELLF +Ve

[0045] Among them, V OCPA and V OCPB These are the overcharge judgment voltage values ​​for the two battery packs, V. CELLF is the upper limit of the individual cell voltage, and Ve is the voltage error value of the battery overvoltage.

[0046] Step 3: Overcharge detection

[0047] Based on the calculated battery pack voltage V OCPA and V OCPB Each of the two battery packs is provided with independent software overcharge protection.

[0048] Energy software collects the voltage V of the two sets of batteries. TA V TB If three consecutive telemetry frames show that the battery telemetry voltage exceeds the overcharge judgment voltage V of the corresponding battery pack, OCPA V OCPB If the charging and discharging regulation circuits of the corresponding battery pack are not charged, charging of the overcharged battery pack will be stopped, and a software overcharge protection alarm flag for the east or west battery pack will be generated remotely.

[0049] After sending a charging prohibition command to the lithium battery charge / discharge regulation circuit corresponding to the overcharged battery pack, the system checks whether the charging current of the overcharged battery pack is zero. If yes, the charging prohibition command is not sent again, and the software function continues. If no, the corresponding charging prohibition command for the overcharged battery pack is sent again, and the system continues to check whether the charging current of the overcharged battery pack is zero. A single command can be sent a maximum of 3 times. If the charging current of the overcharged battery pack is still not zero after the third command is sent, a battery pack charging prohibition function fault alarm flag is generated remotely, and the overcharge protection criterion detection and charging prohibition command sending will no longer be carried out for the overcharged battery pack.

[0050] The software automatically judges the overcharge protection of the battery pack: when the voltage of the overcharged battery pack recovers to below 95% of the overcharge protection voltage value set by the software, the software overcharge protection alarm flag is released, and at the same time, a charging enable command is sent to the lithium battery charging and discharging regulation circuit corresponding to the original overcharged battery pack.

[0051] (5) Figure 4 As shown, the over-discharge judgment and handling strategy for the battery pack is as follows:

[0052] Step 1: Calculate the depth of discharge

[0053] During the satellite's operation in orbit, the state of charge of the two battery banks is calculated and updated in real time based on illumination / Earth (Moon) shadow markers.

[0054]

[0055]

[0056] Step 2: Calculate charging time

[0057] When the energy software receives three consecutive frames of telemetry data simultaneously, and the following conditions are met: the battery discharge current is greater than the first preset threshold (2.8); the bus error amplification signal in the lithium battery charge / discharge regulation device is less than the second preset threshold (10.8), the power management software begins to accumulate battery discharge time in steps of a single software control cycle. When the energy software receives three consecutive frames of telemetry data simultaneously, and the following conditions are met: the battery discharge current is less than the third preset threshold (2.5); the bus error amplification signal in the lithium battery charge / discharge regulation device is greater than the fourth preset threshold (11.5), the accumulation of battery discharge time stops, and two sets of battery discharge times T are obtained. DA and T DB .

[0058] Step 3: Over-discharge flag and overall satellite energy balance processing

[0059] Energy software calculates the state of charge (P) of the battery pack based on three consecutive frames. SOCA and P SOCBIf the value is below the 5th preset threshold, a remote alarm flag for battery pack discharge fault is generated.

[0060] First, send the payload power-off command sequentially, and then send the necessary (enough to maintain the lower limit of the operating temperature of the payload chamber instruments and equipment) payload chamber alternative heater turn-on command and other non-essential automatic heater power-off command.

[0061] After sequentially sending the payload power-off command and other non-essential automatic heater power-off commands, immediately check whether the discharge current of battery group A is less than (P) for three consecutive telemetry physical quantities. SOCA -0.2)C / (1.2-T DA / 3600); At the same time, is the discharge current of battery pack B also less than (P) for three consecutive frames of telemetry physical quantity? SOCB -0.2)C / (1.2-T DB / 3600); If yes, then stop sending power-off commands; otherwise, continue sending power-off commands sequentially.

Claims

1. A spacecraft lithium battery on-orbit high-efficiency autonomous management and protection system, characterized in that, include: The lithium battery charge and discharge regulation device includes several independent lithium battery charge and discharge regulation circuits BCDR, which are divided into two groups, A and B, to charge two groups of lithium-ion battery packs respectively. Each independent BCDR is named BCDRiA or BCDRiB according to the group, where i is the number of the BCDR in the group, and the maximum value of i can be flexibly configured according to the power requirements. A bypass switch is a device used to switch a lithium battery cell or parallel assembly to bypass when the voltage range of a certain lithium battery cell or parallel assembly exceeds a preset threshold range. The central computer communicates with the lithium battery charge and discharge regulation device, collects telemetry data related to charge and discharge regulation, performs autonomous on-orbit charge and discharge management of the lithium battery, and performs fault handling and protection when abnormal telemetry data is detected. The telemetry data includes battery voltage, battery charging current, battery discharging current, and bus voltage amplification signal. The lithium battery charging and discharging regulation device uses hardware circuitry to achieve constant current and voltage limiting control of the lithium battery. The energy software in the central computer autonomously determines whether the battery is in a state of light or shadow, and switches between the light season and the shadow season based on the determination result. The method for determining the state of illumination and Earth-Moon shadow includes the following steps: S1: Determine whether the flag needs to be changed based on the telemetry data from the energy software; S2: Based on the judgment result of S1, when the conversion flag condition is met, the energy software sends a constant voltage charging voltage setting instruction and a constant voltage charging current setting instruction to the lithium battery charging and discharging regulation device, adjusts the instruction code value to the threshold corresponding to the conversion flag, and sets the flag to the conversion flag. In step S1, the condition for switching the light season to the Earth-Moon shadow season is that three consecutive frames of telemetry data satisfy the following: The battery discharge current in the lithium battery charge and discharge regulation device is greater than the first preset threshold. The bus error amplification signal in the lithium battery charge and discharge regulation device is less than the second preset threshold. The condition for switching the Earth-Moon shadow season to the light season is that the duration of T consecutive T LR The telemetry data satisfies: The battery discharge current is less than the third preset threshold. The bus error amplification signal in the lithium battery charge / discharge regulation device is greater than the fourth preset threshold.

2. The system according to claim 1, characterized in that, After the energy software is initialized, the light-Earth-Moon shadow flag defaults to the light season. When the light-Earth-Moon shadow flag is the light season, the conversion condition detection for switching from the Earth-Moon shadow season to the light season is not performed, but the conversion condition judgment for switching from the light season to the Earth-Moon shadow season is detected in real time.

3. An overcharge protection method, characterized in that, The spacecraft lithium battery on-orbit high-efficiency autonomous management and protection system according to claim 1 includes the following steps: A1: The available status indicators of individual battery cells are accumulated in real time through the energy software; A2: Calculate the total number of unusable status flags in each battery pack. Using the given upper limit of the single cell voltage, the given voltage error value of the battery overvoltage, and the aforementioned number of unusable status flags, calculate the overcharge judgment voltage value of the battery pack through the first calculation unit. A3: If three consecutive telemetry frames show that the battery telemetry voltage exceeds the battery pack overcharge judgment voltage, then the following overcharge protection operation will be performed: Send a charging prohibition command to all lithium battery charge / discharge regulation circuits of the corresponding battery pack to stop charging the overcharged battery pack. Generate the corresponding battery pack software overcharge protection alarm flag telemetry.

4. The method according to claim 3, characterized in that, After the charging prohibition command is sent to all lithium battery charging and discharging regulation circuits of the corresponding battery pack in step A3, it is determined whether the charging current of the overcharged battery pack is zero: If the charging current of the overcharged battery pack is zero, the charging prohibition command will no longer be sent, and the software function will continue. If the charging current of the overcharged battery pack is not zero, then the corresponding charging prohibition command for the overcharged battery pack is sent again, and the charging current of the overcharged battery pack is further judged. A single command can be sent a maximum of 3 times. If the charging current of the overcharged battery pack is still not zero after the third command is sent, a battery pack charging prohibition function fault alarm flag will be generated by telemetry, and the overcharge protection criterion detection and charging prohibition command will no longer be sent for the overcharged battery pack.

5. An over-discharge protection method, characterized in that, The spacecraft lithium battery on-orbit high-efficiency autonomous management and protection system according to claim 1 includes the following steps: B1: The energy software collects the light-Earth-Moon shadow marker and the battery voltage value; B2: The second calculation unit calculates and updates the state of charge and depth of discharge of the two battery packs in real time. B3: The energy software collects the discharge current of the battery pack and the bus error amplification signal in the lithium battery charge / discharge regulation device, and accumulates the discharge time T of each of the two battery packs in real time, with a single software control cycle as the step size. D ; B4: If the battery pack's state of charge is below the 5th preset threshold for 3 consecutive frames, a battery pack discharge fault alarm flag will be generated remotely.

6. The method according to claim 5, characterized in that, When generating the battery pack discharge fault alarm sign telemetry in step B4, first send the payload power-off command in order of payload importance from low to high, and send the necessary payload compartment replacement heater turn-on command and other non-essential automatic control heater power-off command. After sequentially sending the payload power-off command and other non-essential automatic heater power-off commands, immediately check whether the battery pack discharge current is less than (P) for three consecutive frames of telemetry physical quantity. SOC -0.2)C / (1.2-T D / 3600); where C is the battery pack capacity, P SOC For calculating the state of charge of the battery pack, T D The calculation determines the battery discharge time; if the result is yes, the power-off command is stopped; if the result is no, the power-off command is sent sequentially.

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