JPH03217399A - Spin stabilizing type satellite - Google Patents

Abstract

PURPOSE:To reduce an electrical burden received by a battery at the shade by utilizing a fact that electromotive force is produced in a gap with a central part piezoelectric ceramic when centrifugal force is added to a circumferential part piezoelectric ceramic provided in the inner part of a solar cell by means of a satellite spin. CONSTITUTION:A spin stabilizing type satellite is stabilized of its attitude when it is rotated in a spin direction 2 with a spin shaft as the center. In this case, a cylindrical circumferential part piezoelectric ceramic 13 is installed in the inner part of a solar cell panel 3 mounted on an outer surface of the circumferential part and a central part piezoelectric ceramic 15 unified with a central cylinder 14 or a satellite main structural body in place around the spin shaft 1 nearer to a center-of-gravity point or the satellite mass center, respectively. Then, electromotive force being produced in space between these ceramics 13 and 15 by means of centrifugal force attending on a satellite spin is fed to a battery 10 and a current consumer 11 through a backstop diode 6, a shunt regulator 7, an error amplifier 8 and a boost converter 9 together with output of the solar cell panel 3.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention converts the centrifugal force associated with satellite spin into electrical energy using piezoelectric ceramics and supplies it to the load along with each output of the battery solar panel. This technology relates to spin-stabilized satellites that reduce the electrical power burden on batteries and compensate for the decline in output from solar panels due to radiation degradation.

[Prior art] Figure 5 is an external view of a conventional spin-stabilized artificial satellite.
FIG. 6 is a block diagram showing a power control system using a partial shunt regulator system, which is a typical power control system for conventional spin-stabilized artificial satellites. In the figure, (
1) is the spin axis, which is the axis around which the satellite rotates (spins), (
2) is the spin direction indicating the direction in which the satellite rotates (spins), (3) is the solar panel that supplies power to the load during sunshine hours, (4) is the thermal shield that blocks heat input from the sun, and (5) (6) is the earth-oriented antenna that rotates in the opposite direction to the satellite and always points toward the earth, and (6) is the backflow prevention 1 installed to prevent the backflow of shunt current in the power control system.
1-diode, (7) shunts a part of the solar panel output according to the control current output from the error amplifier.
(8) is an error amplifier that outputs a control current that compensates for negative power consumption and fluctuations in solar panel output; (9) is this error amplifier. a boost converter that controls the battery voltage according to the control current from (10
) is batch IJ, (1
1) is the load on satellite equipment, heaters, etc. In addition, Figure 7 is a characteristic diagram showing the typical aging characteristics of the power generated by the solar cell Nokufunu (3) in geostationary orbit.
V, S, A, and W indicate the vernal equinox, summer solstice, autumnal equinox, and winter solstice, respectively. Furthermore, Pt. indicates the power consumption of the load (■1), and the shaded area indicates the decreasing output power of the solar panel, mainly due to radiation deterioration in orbit.

Conventional spin-stabilized satellites are configured as described above.
As shown in Figure 5, the posture is stabilized by rotating around the spin axis (1) in the spin direction (2), and the solar panel (3) mounted on the circumference is irradiated with sunlight. In this way, the power required by the load (11) was obtained. In addition, in the shade, the battery (10) shown in Figure 6 supplied the required power. In this power control system, the output of the solar panel (3) exceeds the power consumption of the load (1l),
When the primary power supply voltage fluctuates, the error amplifier (8) compares it with the reference voltage and amplifies the control current, and sends it to the shunt regulator (7). Shunt regulator (7)
divides a part of the output power of the solar panel (3) according to the control current by the transistor acting as a rectifier (
By passing it through the pure resistance inside the shunt, it is converted into Joule heat and released. Therefore, the primary power supply voltage is stabilized. Conversely, the power consumption of the load (l1) is the same as that of the solar panel (3
), and the primary power supply voltage fluctuates, the control current from the error amplifier (8) will flow to the boost converter (
9). The boost converter (9) performs pulse width control in accordance with the control current to compensate for only the difference obtained by subtracting the output voltage of the battery (10) from the satellite bus voltage, thereby stabilizing the primary power supply voltage. Solar panel (3)
As shown in Figure 7, the generated power was gradually decreasing, mainly due to deterioration due to radiation in orbit.

[Problem to be solved by the invention] Conventional spin-stabilized artificial satellites have a mechanism to supply the output power of the solar panel to the load as described in 1. Therefore, the output of the solar panel becomes zero. Because the power burden on the battery increases in the shade, the maximum depth of discharge of the battery is the limit for broadcasting satellites and communication satellites that are equipped with many traveling wave tubes and transmitters, and whose equipment consumes a large amount of power. However, there was an issue in which the battery life would be shortened as a result. Another problem was that the output power of the solar panels gradually decreased, mainly due to deterioration of the solar panels in orbit over their lifetime. Furthermore, since the power generated by the satellite system is determined by the mounting area of the solar panel on the satellite, the power consumption of the Missicon equipment is When the number of solar cells increased, it became necessary to increase the mounting area of the solar cell panels, which caused the problem of affecting the fairing interface, which is the mechanical interface with the launch vehicle.

This invention was made to solve this problem, and by applying centrifugal force due to the spin of the satellite to the circumferential piezoelectric ceramic/cushion provided inside the solar cell, By utilizing the electromotive force generated between the central piezoelectric ceramic and the central piezoelectric ceramic, we aim to create a spin-stabilized satellite that can reduce the power burden that occurs when the sun is out, and compensate for the decrease in the output of solar panels. purpose.

[Means for solving the problem 1 The spin-stabilized artificial satellite according to the present invention is... The electromotive force generated by the centrifugal force during spin is used between the circumferential piezoelectric ceramics provided inside the solar panel and the center piezoelectric ceramics provided around the spin axis at the center of gravity. By supplying the piezoelectric ceramic output to the load along with the battery panel output, it reduces the power burden placed on the battery in the shade and compensates for the drop in output power that is mainly caused by radiation degradation of the solar panel.

[Operation 1] In this invention, centrifugal force accompanying the spin of the satellite is applied to the piezoelectric ceramics provided inside the solar cell panel in the circumferential portion. This centrifugal force induces an amount of electricity (charge) inside the piezoelectric ceramic as stress, creating a potential difference between the piezoelectric ceramic at the center of gravity, where no stress is applied. By electrically connecting ceramics with this potential difference to a solar panel, electric power corresponding to the centrifugal force is supplied to the load along with the output of the solar panel.

[Example] Fig. 1 is an external view of a spin-stabilized artificial satellite that is an embodiment of the present invention, Fig. 2 is a sectional view of a spin-stabilized artificial satellite that is an embodiment of the present invention, and Fig. 3 is a cross-sectional view of a spin-stabilized artificial satellite that is an embodiment of the present invention. The figure shows a block diagram of a power control system of a spin-stabilized artificial satellite, which is an embodiment of the present invention. In the figure, (1) to (l1) are exactly the same as the conventional device described above, and (12) shows that the centrifugal force (I3) acting outward from the satellite spin is generated by a cylindrical device installed inside the solar panel. Circumferential piezoelectric ceramics, (14)
(15) is the central cylinder which is the satellite structure, and (15) is the central piezoelectric ceramics provided around the spin axis at the center of gravity.

FIG. 4 is a characteristic diagram showing the predicted aging characteristics of piezoelectric ceramic output power in a geostationary orbit of a spin-stabilized artificial satellite, which is an embodiment of the present invention.
, W indicate the vernal equinox, summer solstice, autumnal equinox, and winter solstice, respectively. Nao P
t. indicates the power consumption of the load (1l), and for ease of comparison, the output power characteristics of the solar panel (3) are also shown with a broken line. The spin-stabilized artificial satellite of this embodiment is configured upward, and as shown in FIG. 1, its attitude is stabilized by rotating in the spin direction (2) around the base. Here, inside the solar cell panel (3) mounted on the outer surface of the circumferential part, a cylindrical circumferential piezoelectric ceramic (I3) is mounted around the spin axis near the center of gravity, which is the center of mass of the satellite. is integrated with the central cylinder (l4), which is the main structure of the satellite, and is made of piezoelectric ceramics (l4) in the center.
5) is. They are provided as shown in the sectional view of FIG. 2, respectively.

The physical forces that act on an artificial satellite, which is a spacecraft orbiting in orbit, are centered around the center of gravity, which is the center of mass of the satellite, and the gravitational force acting on the earth side, and the force acting on the center of gravity as the satellite orbits the earth. Centrifugal force acting on the anti-Earth side and spin In the satellite, the rotation (spin) of the molar body is centered around the center of gravity, and the spin axis (
1) can be roughly divided into three types: centrifugal force that acts outward. Each force acts more strongly as the distance from the center of gravity increases. Therefore, these forces hardly act on the center of gravity, which is the center of action of the force, and the center of gravity that is farthest from the spin axis (1) As shown in Figures 1 and 2, the centrifugal force (l2) and the above-mentioned earth's gravitational force are applied as stress to the circumferential piezoelectric ceramic (l3) located at the circumferential part of the satellite, and the piezoelectric ceramic (l3) is placed at the center of mass of the satellite. Almost no physical force is applied to the central piezoelectric ceramic (15), which is provided integrally with the central cylinder (14) around the spin axis near a certain center of gravity. The stress applied to the circumferential piezoelectric ceramic (15) induces an amount of electricity (charge) within the ceramic according to the stress, and a gap between the piezoelectric ceramic (15) at the center and the piezoelectric ceramic at the center (15) where almost no physical force acts. Generates a potential difference. Each ceramic with this potential difference is connected to a solar cell panel (as shown in the block diagram in Figure 3).
3), and electric power proportional to the magnitude of the stress applied to the circumferential piezoelectric ceramic (13) is supplied to the load (11) together with the output of the solar panel (3). Stabilization against fluctuations in the primary power supply voltage is established by the operation of the shunt regulator (7), error amplifier (8), boost converter (9), and battery (10) similar to the conventional device described in section 2. The electric power supplied to the load from piezoelectric ceramics is produced as long as the J star orbits the earth and continues to rotate (spin). 2, and there is almost no drop in torque due to radiation deterioration in orbit, so it is predicted that the aging characteristics shown in Figure 4 will be the same forever, regardless of whether it is exposed to sunlight or shade. be done. Therefore, the solar gamma pond panel (
Unlike the output power in 3), it does not gradually decrease from the spring equinox, summer solstice, autumn to winter solstice. As described above, the spin-stabilized artificial star grabper, which is an embodiment of the present invention, can generate the same power as I; semi-permanently, regardless of shade or sunlight, throughout its lifetime, as shown in Figure 4. can be supplied to the load.

[Effects of the Invention] As explained above, the present invention can supply approximately the same amount of power to the load, regardless of shade or sunlight, independently of the output of the solar cell panel. Therefore, the battery exhaustion depth of discharge in the shade when the solar cell panel output becomes zero is suppressed to a small value, the electric power burden on the battery is reduced, and the battery life is extended. Furthermore, it has the effect of compensating for the drop in solar panel output power during sunlight, which is mainly caused by radiation deterioration of solar panels in orbit. Additionally, power can be supplied to the load from a route completely different from the solar panel output. This has the effect of responding to increased power consumption of mission equipment without increasing the mounting area of the solar panel, which in other words does not impact the fairing interface, which is the mechanical interface with the launch vehicle.

[Brief explanation of drawings]

Fig. 1 is an external view of a spin-stabilized artificial satellite that is an embodiment of the present invention, Fig. 2 is a sectional view of a spin-stabilized artificial satellite that is an embodiment of the present invention, and Fig. 3 is an external view of a spin-stabilized artificial satellite that is an embodiment of the present invention. Figure 4 is a block diagram of the power control system of a spin-stabilized artificial satellite, which is an embodiment of the present invention, and shows the prediction of the aging characteristics of piezoelectric ceramic output power in the geostationary orbit of a spin-stabilized satellite, which is an embodiment of the present invention. V, S, A, and W indicate the vernal equinox, summer solstice, autumnal equinox, and winter solstice, respectively. PL indicates the power consumption of the load, and the broken line indicates the output power characteristics of the solar panel. Figure 5 is an external view of a conventional spin-stabilized artificial satellite.
Figure 6 is a block diagram showing a power control system using the partial shunt regulator method, which is a typical power control method for conventional spin-stabilized satellites, and Figure 7 shows the power generated by solar panels in geostationary orbit. It is a characteristic diagram showing typical aging characteristics, and V, S, A. W indicates the vernal equinox, summer solstice, autumnal equinox, and winter solstice, respectively; tPL indicates the power consumption of the load; and the shaded area indicates the decreasing output power of the solar battery panel mainly due to radiation deterioration in orbit. In the figure, (l) is the spin axis, (2) is the spin direction, (3) is the solar panel, (4) is the thermal shield 2, (5) is the earth-oriented antenna, (6) is the backflow prevention diode, (7
) is the shunt regulator, (8) is the error amplifier, (9
) is the boost converter, (IQ) is the battery.
<11) is the load (I2) is the centrifugal force, (13) is the circumferential piezoelectric ceramic (14) is the central cylinder,
(15) shows the piezoelectric ceramic center. In addition, the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] A solar panel that supplies power to loads in orbit, a thermal shield that blocks heat input from the sun,
A cylindrical circumferential piezoelectric ceramic provided inside the solar panel, a central cylinder that is the satellite structure,
An earth-oriented antenna that is always directed toward the earth, a piezoelectric ceramic in the center near the center of gravity around the satellite spin axis, and a shunt current that controls the power supplied to the load from each piezoelectric ceramic and solar panel. A backflow prevention diode that prevents backflow, a shunt regulator that converts the power corresponding to the shunt current into thermal energy as surplus power using a pure resistance, and releases and removes it, and outputs for the power consumption of the load, solar panel, and piezoelectric ceramics. It consists of an error amplifier that outputs a control current to correct power fluctuations, a battery that supplies power to the load during shade, and a boost converter that controls the battery voltage according to the control current from the error amplifier. By using the electromotive force generated between the circumferential piezoelectric ceramics and the center piezoelectric ceramics, it can reduce the electrical burden on the battery by supplying power to the load together with the battery when in the shade, and A spin-stabilized artificial satellite that compensates for the decrease in output of solar panels due to radiation degradation.