RU2470440C2 - Method to control autonomous system of spacecraft power supply - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: invention relates to power supply systems (PSS) of spacecrafts (SC). According to the invention, the method for control of an autonomous SC PSS comprising a solar battery (SB) and "N" accumulator batteries, every of which comprises "n" serially joined accumulators, where "N">1, a voltage stabiliser connected between the SB and the load and "N" charging devices (CD) and discharge devices (DD), consisting in control of the voltage stabiliser and CD and DD depending on input and output PSS voltage, extent of charge and discharge of the AB, prohibition for operation of the appropriate CD in achievement of the limit level of such AB charge, removal of this prohibition whenever a certain level of such AB discharge is achieved, prohibition for operation of the appropriate DD whenever the limit value of such AB discharge is achieved, removal of this prohibition whenever a certain level of such AB charge is achieved, prohibition for operation of all DD, when capacities of DD that remained in operation are not sufficient for load supply. In process of discharge the level of AB charge is monitored by voltage, or voltage of each AB accumulators.

EFFECT: increased reliability of PSS by prevention of a failure of lithium-ion AB accumulators.

2 cl, 2 dwg

Description

The invention relates to electrical engineering, namely, power supply systems (SES) of spacecraft (SC), using solar batteries (SB) as primary energy sources, and storage batteries (AB) as energy storage devices.

A known method of controlling an autonomous power supply system (RF patent No. 2059988, H02J 7/35) containing a solar battery (SB), a voltage regulator included between the solar battery and the load, n batteries (n≥1) and n (according to the number of batteries ) charging and discharging devices, as well as for each battery - devices for monitoring the degree of charge.

In the known SES, the voltage stabilizer, charging and discharge devices are continuously controlled depending on the input (voltage of the SB) and the output voltage of the SES. At the same time, the chargers provide a charge for the battery, and the voltage stabilizer and discharge device provide power to consumers.

The continuous control (feedback) circuits of the charger are connected to the SB bus and the load bus, and the continuous control circuits of the voltage stabilizer and discharge device are connected to the load bus.

Depending on the degree of charge or discharge of the battery, a prohibition or authorization of the operation of the charger and the discharge device is carried out.

Such management provides long-term autonomous operation of the SES. However, it does not ensure the preservation of the performance of SES in case of emergency or emergency situations on the spacecraft. In the event of an abnormal, unplanned violation of the orientation of the solar cells of the spacecraft to the sun, a violation of the energy balance in the SES occurs. If the loss of orientation is long enough, a complete discharge of all batteries may occur. Food on-board consumers will then stop. In the case of lithium-ion batteries, their full discharge will lead to irreversible battery failure.

A known method of controlling an autonomous power supply system (RF patent No. 2168828, H01J 7/36) containing a solar battery and n rechargeable batteries, where n≥1 is a voltage regulator connected between the solar battery and the load and n charge and discharge devices, which consists in control the voltage stabilizer and charge-discharge devices depending on the input and output voltage of the system, control the degree of charge and discharged batteries, prohibit the operation of the corresponding charger p Upon reaching the maximum charge level of a given battery, removing this prohibition upon reaching a certain level of discharging a given battery, prohibiting the operation of a corresponding discharge device when reaching a maximum level of discharging a given battery, lifting this prohibition upon reaching a certain charge level of a given battery, characterized in that in the case of a loss of orientation of solar panels in the sun, emergency discharge of battery batteries it and disconnecting part of the discharge devices, when the power of the remaining discharge devices is not enough to power the load, prohibit the operation of all discharge devices and the voltage regulator, and also stop the management of discharge devices by signals about the level of charge, after which, if there is a danger of battery reversal of some battery batteries connect a battery protection device against reverse polarity to it, after restoring the orientation of solar batteries to the Sun, first produce a charge and battery; to a capacitance value, and then allow the voltage stabilizer job and resume control bit devices by signals on the level of charge, battery protection device against polarity disconnected after the start of the battery charge.

This method is adopted as a prototype of the claimed invention. The known method solves the problem of preventing the failure of batteries AB, restore the normal functioning of the SES after an emergency or emergency. However, it is inoperative when using lithium-ion batteries. So, for example, battery protection devices against reverse polarity are problematic (rather impossible) to implement in the absence of primary power source power - SB.

In addition, the known method does not take into account that:

1. The battery remains connected via unregulated discharge circuits, decoupled by diodes in the direction of discharge current flow, the generalized SB-AB bus used to connect the most critical SES units;

2. The presence of devices for monitoring the status of the battery and so on. Therefore, along with the self-discharge of the battery, there is also a certain current of the external discharge of the battery. Complete disconnection of control devices from the battery is most often impractical.

The objective of the invention is to increase the reliability of SES by preventing the failure of lithium-ion batteries and restore the normal functioning of SES during and after an emergency or emergency.

The problem is solved in that, when using lithium-ion batteries as batteries, during the discharge, the charge level is controlled by their voltage or the voltage of the batteries of each battery, in addition, the load is divided into standby and session components, while , in the event of a loss of orientation of the solar batteries in the Sun, an emergency discharge of the batteries and disconnection of part of the discharge devices, when the capacities of the remaining discharge devices are insufficient precisely to power the load, first they generate a signal to disconnect the session load, then prohibit the operation of all discharge devices, additionally block consumption by unregulated discharge circuits of the batteries, and after restoring the orientation of the solar batteries to the Sun and charging the batteries to a predetermined voltage value, the ban on operation of discharge devices and locking by unregulated discharge circuits of batteries. In addition, the operation of all discharge devices is prohibited when the voltage on the battery reaches at least (2.7n + ΔU (n-1)), V, or the voltage on any battery is at least 2.7 V, where ΔU is the maximum allowable imbalance of batteries by voltage, V.

When each battery is discharged to the lower set level, this battery is put into storage mode.

After disconnecting the corresponding discharge device, the load is powered by the remaining switched on discharge devices from other batteries that have not yet reached the set discharge level.

If, after the prohibition of the operation of several discharge devices, the remaining battery power and the corresponding discharge devices is not enough to provide power to the on-board consumers, they generate a signal to disconnect the session load and, if this does not lead to an increase in the battery voltage, the operation of all discharge devices is prohibited. A signal to switch the SES to storage mode can also be a decrease in the voltage on the output buses of the SES to a certain value (with a lack of power of the working discharge devices, the output voltage of the SES will begin to decrease).

It should be noted that the session load (for communication spacecraft this is mainly a relay) is designed to operate in a narrow range of supply voltage, while the standby load (thermal control systems, orientation, command-measuring, etc.) should remain operational in the range of the supply voltage from zero to the rated value and slightly higher.

Thus, in the event of an abnormal or emergency situation at the facility (loss of SB orientation on the Sun), a signal is first generated to disconnect the session load, after which the operation of all discharge devices is prohibited, they additionally block consumption through unregulated discharge circuits of the batteries, which avoids critical discharge of batteries AB, leading to their failure, and also to protect the session load from the effects of unauthorized supply voltage.

In the event of a random appearance of the SB illumination or restoration of the SB orientation on the Sun, the AB charge will begin to be realized. Some time after the start of the charge, the voltage on the batteries will increase above the minimum acceptable (set) level.

Upon reaching the required level of charge of the batteries, the ban on the operation of all discharge devices and the blocking of consumption through unregulated discharge circuits of the batteries are lifted. Power supply for on-board consumers is renewed from a voltage stabilizer or from discharge devices, depending on the ratio of the load power and the power generated by the power supply. Since the batteries are charged, the voltage at the output of the SES will be equal to the nominal.

Figure 1, shows a functional diagram of an autonomous spacecraft power supply system for implementing the proposed method.

The autonomous power supply system of the spacecraft contains a solar battery 1 connected to load 2 through a voltage stabilizer 3, rechargeable batteries 4 ₁ -4 _n connected through chargers 5 ₁ -5 _n to solar battery 1, and through discharge devices 6 ₁ -6 _n voltage stabilizer output filter input 3.

At the same time, load 2 in its composition contains an on-board computer, a telemetry system and a command-measuring radio line. In addition, the load is divided into standby and session components (not shown in the diagram).

In parallel with the batteries 4 ₁ -4 _{n, the} battery monitoring devices 7 ₁ -7 _n are connected, connected by the input to the batteries 4 ₁ -4 _n to control the voltage of the batteries, and the output with a load of 2.

Measuring shunts 8 ₁ -8 _{n are} installed in the battery charge-discharge circuit.

Chargers 5 ₁ -5 _n consist of a control key 9, controlled by a control circuit 10, a boost assembly made on a transformer 5-3, transistors 5-1 and 5-2, and a rectifier on diodes 5-4 and 5-5.

The discharge devices 6 ₁ -6 _n consist of a control key 11 controlled by a control circuit 12.

The voltage stabilizer 3 consists of a control key 13, controlled by a control circuit 14, an input filter on the capacitor 15 and an output filter on the diode 17, the inductor 18 and the capacitor 16.

Schemes 10 chargers May ₁ -5 _n, 12 bit devices June ₁ -6 _n, voltage stabilizers 14 3 are formed as pulse width modulators, the input connected to the stabilized voltage busbars. The control circuit 10 of the chargers 5 ₁ -5 _{n are} additionally associated with measuring shunts 8 ₁ -8 _n and load 2.

The generalized bus SB-AB 19, used to connect the most critical nodes of the SES, is connected to the solar 1 and rechargeable 4 ₁ -4 _n batteries through diodes 21, 20 and 22, respectively, while switches 23 and 24 are controlled in the communication circuits with AB load 2.

The device operates as follows. During operation, rechargeable batteries 4 ₁ -4 _n operate mainly in storage mode and periodic recharges from the solar battery 1 through chargers 5 ₁ -5 _n . This mode of operation allows you to keep them in constant readiness in case of emergencies (loss of satellite orientation on the Sun) or the passage of regular shadow areas of the orbit.

Power supply load 2 is provided from the solar battery 1 through the voltage stabilizer 3.

When passing shadow portions of the orbit or in violation of orientation, load 2 is powered by batteries 4 ₁ -4 _n through discharge devices 6 ₁ -6 _n .

Battery monitoring devices 7 ₁ -7 _n control the voltage of the battery batteries 4 ₁ -4 _n and transmit information about their condition to load 2. The voltage of the battery as a whole can be calculated by summing the voltage of the batteries.

During the operation of the spacecraft, according to the results of the analysis of information about the state of the battery (mainly the voltage of the batteries and the battery as a whole), a ban on the operation of all discharge devices and blocking of uncontrolled discharge circuits of the battery is formed according to a program previously set in the onboard computer. The lifting of the ban and blocking can also be carried out according to the program or by command from the Earth through the command and measurement radio line after analyzing the telemetry information from the spacecraft.

This situation will occur in the event of a loss of orientation of the solar cells of the spacecraft on the Sun, an emergency discharge of the batteries and disconnection of some of the discharge devices when the power of the remaining discharge devices is insufficient to power the load. In this case, at first, a signal is generated to disconnect the session load and only after that the operation of all discharge devices is prohibited, the consumption is additionally blocked by unregulated discharge circuits of the batteries.

When using lithium-ion rechargeable batteries as rechargeable batteries, during the discharge, the charge level of the batteries is controlled by their voltage or the voltage of the rechargeable batteries of each rechargeable battery.

At the same time, the operation of all discharge devices is prohibited when the voltage on the battery reaches at least (2.7n + ΔU (n-1)), V, or the voltage on any battery is at least 2.7 V, where n is the number of batteries in the battery, a ΔU is the maximum allowable voltage imbalance of the batteries, V.

Figure 2 shows the discharge characteristic of the lithium-ion battery LIGP-10A, manufactured by the company OJSC "Saturn", Krasnodar.

As can be seen from the drawing, by the nature of reducing the battery voltage, at a voltage of 2.7 V, the capacity in the battery is minimal.

If the battery is controlled by its total voltage, it is necessary to multiply 2.7 V by the number of batteries in the series battery circuit and add a value (correction) that takes into account the permissible battery voltage imbalance. At the same time, choose the “worst” option when all the batteries, except for one, are equal in voltage and exceed the mentioned one by the value of the permissible voltage imbalance.

After restoring the orientation of solar batteries to the Sun and charging batteries to a predetermined voltage value, the ban on the operation of discharge devices and blocking by unregulated discharge circuits of batteries is removed.

Thus, the claimed method of controlling the autonomous power supply system of the spacecraft ensures the prevention of failure of lithium-ion batteries and restoration of the normal operation of the SES during and after an emergency or emergency of the spacecraft, which increases the reliability of the spacecraft and the spacecraft as a whole.

Claims (2)

1. A method for controlling an autonomous power supply system of a spacecraft containing a solar battery and “N” rechargeable batteries, each of which consists of “n” series-connected batteries, where “N” ≥1, a voltage regulator connected between the solar battery and the load and “ N ”of charging and discharging devices, which consists in controlling the voltage stabilizer and charging and discharging devices depending on the input and output voltage of the power supply system, the degree of charge and discharge batteries, the prohibition of the operation of the corresponding charger when reaching the maximum charge level of this battery, the removal of this ban upon reaching a certain level of discharge of the battery, the ban on the operation of the corresponding discharge device when the limit is reached, the discharge of this battery when a certain level of charge of the battery, the prohibition of all discharge terns, when the power of the remaining discharge devices is not enough to power the load, characterized in that when using lithium-ion batteries as batteries, during the discharge, the charge level is controlled by their voltage or the voltage of the batteries of each battery, in addition, the load is divided into standby and session components, in the case of a loss of orientation of the solar cells in the sun, emergency discharge of the batteries and disconnection of part p charging devices, when the power of the remaining discharge devices is not enough to power the load, first they generate a signal to disconnect the session load, then they prohibit the operation of all discharge devices, additionally block consumption by unregulated discharge circuits of the batteries, and after restoring the orientation of the solar batteries to the Sun and the battery charge to a predetermined voltage value removes the ban on the operation of discharge devices and locks on unregulated discharge circuits mutator batteries. 2. The control method for the autonomous power supply system of the spacecraft according to claim 1, characterized in that the operation of all discharge devices is prohibited when the voltage on the battery reaches (2.7 · n + ΔU · (n-1)), V, or voltage on any 2.7 V battery, where ΔU is the maximum allowable voltage imbalance of the batteries, V.

Images