RU2486634C2 - Operating procedure for pack of nickel-hydrogen batteries in power supply system of geostationary satellite - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: prohibition of charge and preventive discharge are made before commencement of orbital eclipse period, at that discharge capacitance is evaluated with respect to its sufficiency for the next orbital eclipse periods; when required preventive discharge is repeated.

EFFECT: increase of reliability and efficiency of operation for the pack of nickel-hydrogen batteries and reliability of satellites intended use.

3 cl, 1 dwg

Description

The invention relates to the electrical industry and can be used in the operation of nickel-hydrogen storage batteries (AB) in power supply systems of spacecraft (SC), operating in geostationary orbit.

When using a set of nickel-hydrogen storage batteries in the power supply system of a geostationary spacecraft, it is necessary to take into account the specifics of the battery in geostationary orbit. It consists in the following: in orbits with 100% illumination, for two periods of 5 months each year, the batteries are continuously in the “shallow” citation mode in a state close to full charge. When you turn on the electro-reactive propulsion system (for example, a stationary plasma engine) to correct the orbit, which can occur twice a day, it is possible to discharge the battery to a limited capacity. This discharge mode for AB is not critical and test. The most critical period for AB is the spacecraft in orbit with shadow areas (periods in the equinox). With a gradual increase in the duration of the shadow, the depth of the discharge of the battery increases from 0 to maximum at a maximum duration of the shadow of 1.2 hours and then decreases to zero. The method of operating a set of nickel-hydrogen storage batteries in the power supply system of a geostationary spacecraft should ensure timely preventive measures that restore the current capacity of storage batteries before passing through the shadow areas of the orbit and eliminate unplanned interruptions in the operation of the target spacecraft equipment.

A known method of operating nickel-hydrogen storage batteries according to the patent of the Russian Federation No. 2289178, which consists in the fact that they conduct charge-discharge cycles, monitor the voltage of each battery and the battery as a whole, determine the current discharge and charge capacities, as well as the charge current, charge the battery direct current to the value (0.6-0.8) of the rated capacity. Before the start of the shadow sections of the geostationary orbit, the AB recovery and charge-discharge cycle is performed, while the discharge is carried out for resistance by the value determined by the formula

$$R=n\cdot \frac{1.25\cdot T_0}{C_{n\mathrm{about}m}}$$

where n is the number of batteries in the Nickel-hydrogen battery;

1.25 - the average discharge voltage of the batteries;

T _o - discharge time, h;

C _nom - the nominal capacity of the Nickel-hydrogen battery,

with the discharge limited by the voltage equal to the number (n-1) of batteries in the battery for 40-50 hours (T ₀ ), and the charge is carried out by a current of at least 0.15 of the nominal capacity.

The disadvantage of this method is that it does not regulate the following important operational aspects of working with AB:

1) verification of the readiness of AB to pass the shadow areas;

2) technology for assessing the current discharge capacity of AB;

3) carrying out, if necessary, recovery actions with subsequent monitoring of their effectiveness.

In addition, the discharge of the batteries in the known method is limited based on the state of charge of any battery, which limits the possibility of using the entire capacity of the battery.

All this reduces the reliability and operational efficiency of the AB, in particular, and the reliability of the intended use of the spacecraft as a whole.

The closest technical solution is the method of operating nickel-hydrogen storage batteries according to the patent of the Russian Federation No. 2399122, selected as a prototype, which consists in the fact that periodically, for example once every 6-9 months, a charge ban is introduced for one of the batteries, as a discharge loads use the on-board equipment of the spacecraft, the voltage value of the battery is selected as a criterion for limiting the depth of the discharge, and the value of the boundary voltage level is set in volts equal to the number n or (n + 1) of batteries in the battery the battery, upon reaching which the ban on the battery charge is lifted, thereby including it in its normal operation, the values of the charging capacity of the alarm pressure sensor and the maximum battery voltage during charging, determined during the completion of the molding cycle, are used to assess the condition of the battery and predict its degradation , a similar sequence of operations is repeated for the subsequent AB, while the period of time from the completion of the molding cycle of one AB to the start of the molding cycle of another A B is selected based on the temperature condition of the formed AB.

The disadvantage of this method is that it is focused on the operation of the set of batteries in low-orbit spacecraft and does not take into account the specifics of the spacecraft in the geostationary orbit, which reduces the reliability and efficiency of operation of the battery, in particular, and the reliability of the intended use of the spacecraft as a whole.

The task of the invention is to increase the reliability and operating efficiency of a set of nickel-hydrogen storage batteries and the reliability of the intended use of spacecraft.

The problem is solved in that when operating a set of nickel-hydrogen storage batteries in the power supply system of a geostationary spacecraft, which consists in carrying out charges, storing charged and discharged charges, when the degree of charge of the batteries is limited by the level of hydrogen pressure in the batteries, the parameters of each a battery, for example, electric capacity, battery voltage and temperature, periodically introduce a charge prohibition for one from the batteries and carry out its preventive discharge with restriction by a given criterion, after which the ban on the charge of the battery is lifted, including thereby its normal operation, the same sequence of operations is repeated, if necessary, for other batteries, the charge is prohibited and the preventive discharge is carried out before the beginning of the shadow sections of the orbit, the size of the discharge electric capacitance is assessed for its sufficiency for passing through the subsequent shadow sections, if necessary ti prophylactic discharge is repeated. At the same time, the depth of the preventive discharge of the battery is selected by the minimum value of its voltage, at which a stable voltage level at the output of the power supply system of a particular structure is provided. In addition, if the discharge electric capacitance does not correspond to a value sufficient for passing the subsequent shadow sections, the subsequent charging electric capacitance is converted to a discharge one using the formula C _p = c _s · η _s ,

where C _p - discharge capacity of the battery, A * h;

C _s - charging capacity of the battery, A * h;

η _z - the efficiency of the process of charging the battery,

and the result obtained is used to estimate the value of the discharge electric capacitance for its sufficiency for the passage of subsequent shadow areas.

Indeed, modern nickel-hydrogen storage batteries used in space technology include bypass diodes that shunt batteries in the discharge direction when a battery is completely discharged. The presence of these discharge diodes (with a low voltage drop of less than 0.3 V) allows you to discharge the batteries (without risk of disabling any battery) to their maximum depth, determined by the total minimum voltage of the battery, which ensures a stable voltage level at the system output power supply of a specific structure. In other words, use the energy available in the battery to the maximum.

Carrying out a deep preventive battery discharge helps to work out the active mass of the batteries and, accordingly, reduce their internal resistance, reduce the unbalance of the batteries by capacity, which ultimately increases its current capacitive capabilities. In this case, the fact of increasing the capacity of the battery after a preventive discharge can be seen on a subsequent charge or on a repeated cycle. A deeper preventive discharge gives a more complete effect, and the discharge capacity of the battery can be estimated by its subsequent (after the discharge) charging capacity, recounting it into the discharge according to the formula Сp = с _з · η _з ,

where C _p - discharge capacity of the battery, A * h;

C _s - charging capacity of the battery, A * h;

η _z - the efficiency of the battery charge process.

Figure 1 shows the functional diagram of the autonomous power supply system of the spacecraft for the implementation of the proposed method.

The autonomous power supply system of the spacecraft contains a solar battery 1 connected to load 2 through a voltage converter 3, rechargeable batteries 4 ₁ -4 _n connected through charging converters 5 ₁ -5 _n to the solar battery 1, and through discharge converters 6 ₁ -6 _n to the input of the output filter of the voltage converter 3. In addition, the batteries 4 ₁ -4 _n contain bypass discharge circuits consisting of diodes connected in parallel to each battery in the discharge direction.

At the same time, load 2 in its composition contains an on-board computer, a telemetry system and a command-measuring radio line.

In parallel with the batteries 4 ₁ -4 _{n, the} battery monitoring devices 7 ₁ -7 _n are connected, connected to the input to the batteries 4 ₁ -4 _n to control the voltage, pressure and temperature of the batteries, and the output with a load of 2. In addition, the battery monitoring devices batteries 7 ₁ -7 _n contain discharge resistance (not shown in the diagram) for conducting preventive discharges of batteries 4 ₁ -4 _n .

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

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

Bit converters 6 ₁ -6 _n consist of a control key 11, controlled by a control circuit 12.

The voltage converter 3 consists of a control key 13, controlled by a control circuit 14, an input filter on a capacitor 3-1 and an output filter on a diode 3-2, a choke 3-3 and a capacitor 3-4.

The control circuits of 10-charge converters 5 ₁ -5 _n , 12-bit converters 6 ₁ -6 _n , 14 - voltage converters 3 are made in the form of pulse-width modulators, the input connected to the stabilized voltage buses. The control circuit 10 of the charging converters 5 ₁ -5 _{n are} additionally associated with the measuring shunts 8 ₁ -8 _n and load 2.

The device operates as follows.

During operation, rechargeable batteries 4 ₁ -4 _n work mainly in storage mode and periodic recharges from the solar battery 1 through charging converters 5 ₁ -5 _n . This mode of operation allows you to keep them in constant readiness for emergencies (loss of spacecraft orientation to the Sun) or for the passage of regular shadow areas of the orbit.

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

When passing shadow portions of the orbit, or if the spacecraft’s orientation to the Sun is disturbed, load 2 is powered by rechargeable batteries 4 ₁ -4 _n through discharge converters 6 ₁ -6 _n .

Monitoring devices 7 ₁ -7 _n control the voltage, pressure and temperature of the battery batteries 4 ₁ -4 _n and transmit information about their condition to the load 2.

During operation of the battery, before the start of the shadow sections of the orbit, the command from the Earth through the command and measurement radio line starts the program for the preventive discharge of any battery. In this case, with the help of the on-board computer, the necessary actions are taken to lock (charge prohibition) and then unlock the operation of the charging converter, turn the preventive discharge on and off, control the discharge and charging capacity, perform calculations and decide on the positive completion of preventive work (completion of the program).

Thus, the application of the proposed method of operating a set of nickel-hydrogen storage batteries in the power supply system of a geostationary spacecraft allows to increase the reliability and efficiency of their operation and the reliability of the target spacecraft use.

Claims (3)

1. The method of operation of a set of nickel-hydrogen storage batteries in the power supply system of a geostationary spacecraft, which consists in carrying out charges, storage in a charged state, recharges and discharges, while the degree of charge of the batteries is limited by the level of pressure of hydrogen in the batteries, the parameters of each battery are controlled , for example, electric capacity, battery voltage and temperature, periodically introduce a charge ban for one of the batteries and carry out its preventive discharge with restriction by a given criterion, after which the ban on the battery charge is lifted, including thereby its normal operation, the same sequence of operations is repeated, if necessary, for other batteries, characterized in that the charge is prohibited and the preventive discharge is carried out before the beginning of the shadow sections of the orbit, the size of the discharge electric capacitance is assessed for its sufficiency for passing through the subsequent shadow sections, if necessary galactic discharge is repeated. 2. The method according to claim 1, characterized in that the depth of the preventive discharge of the battery is selected by the minimum value of its voltage, which ensures a stable voltage level at the output of the power supply system of a particular structure. 3. The method according to claim 1, characterized in that if the discharge electric capacitance does not correspond to a value sufficient for passing the subsequent shadow sections, the subsequent charging electric capacitance is converted to a discharge one according to the formula Cp = c _s · η _s , where
Cp - discharge capacity of the battery, Ah;
With _s - the charging capacity of the battery, Ah;
η _z - the efficiency of the process of charging the battery,
and the result obtained is used to estimate the magnitude of the discharge electric capacity for its sufficiency for the passage of subsequent shadow areas.