JP2016159865A - Solar battery paddle controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the disadvantage of an artificial satellite, specifically, because of the large possibility of a solar battery paddle receiving atmospheric pressure resistance, the effect of orbit altitude reduction is large on the satellite having a large solar battery paddle, and many propellants are necessary to hold the orbit altitude, causing a satellite weight increase.SOLUTION: When a power balance is established within time less than an orbit half round, a solar battery paddle is subjected to tracking control/hold control at a predetermined orbit position establishing the power balance, and coupled by through reverse rotation. When it is necessary to generate power equal to or more than the orbit half round, and when it is not necessary to always generate power by setting the solar battery paddle oppositely to the sun during sunshine, the solar battery paddle is subjected to tracking control/hold control at an orbit position according to necessary power generation time, and coupled by through forward rotation control. Other than this, tracking control/hold control is switched at a boundary between sunshine and shade of the earth to execute through forward rotation control. In the hold control, the solar battery paddle is controlled at a rotational angle where the effect of atmospheric pressure is smallest.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a solar cell paddle control device that controls the rotation of a solar cell paddle in an artificial satellite.

  The solar battery paddle mounted on the artificial satellite converts the energy of sunlight into electric energy and supplies electric power to the satellite system. The solar battery paddle is composed of a structure panel to which a plurality of solar cells are attached, and a drive mechanism for attaching the structure panel to the satellite body so as to be capable of uniaxial drive rotation.

  An artificial satellite for observing the earth needs to always point an observation sensor such as an optical observation device or an antenna toward the earth. On the other hand, the solar cell paddle needs to be directed toward the sun in order to generate electric power, and the drive mechanism rotates the solar cell paddle around a predetermined rotation axis. Thus, the solar cell paddle can be oriented so that the light receiving surface faces the sun, and the required power can be secured. Ordinary artificial satellites always keep track of the sun by rotating the paddle at a constant speed regardless of the shaded area of the earth.

  Also, the solar battery paddle deteriorates over time in its power generation capability throughout the mission period of the satellite due to radiation in the space environment and contamination that adheres to the solar cell surface. For this reason, in consideration of the aged deterioration of the solar cell paddle, the minimum generated power at the end of the mission is designed to be equal to or greater than the maximum power consumption of the artificial satellite.

  In such an artificial satellite, the degree of deterioration of the solar battery cell is small at the beginning of the mission, and the solar battery paddle is always directed to the sun during sunshine. For this reason, surplus power is generated in the generated power of the solar cell paddle. From the above, conventional artificial satellites are provided with a shunt mechanism for dissipating surplus power and a power controller for managing the balance of generated power and power consumption.

  In relation to the above, in Patent Literature 1, the shunt current is detected, and the paddle rotation angle of the solar cell paddle is deviated from the angle facing the sun as necessary, thereby suppressing the paddle generated power.

JP 60-191900 A

  Since the conventional artificial satellite performs tracking control of the paddle so that the solar battery paddle and the sun face each other, the maximum electric power that can always be generated is generated. It is also designed so that the minimum generated power at the end of the mission is greater than the maximum power consumption of the satellite. As a result, a lot of surplus power is generated, and the power is lost by the shunt mechanism.

  In addition, since the artificial satellite receives the resistance of the atmosphere that exists slightly in the space environment, the orbital altitude of the artificial satellite decreases. Atmospheric resistance is proportional to the area projected in the direction of travel of the satellite, and the projected area occupied by the solar cell paddle over the entire satellite is large. Along with this, the solar cell paddle is also subject to atmospheric resistance, so satellites equipped with large solar cell paddles are greatly affected by orbital altitude reduction, and it is necessary to install many propellants to maintain the orbital altitude. is there. Therefore, there is a problem that contributes to an increase in the weight of the artificial satellite.

  The present invention has been made to solve the above-mentioned problems, and it is intended to reduce the influence of atmospheric resistance on a solar cell paddle without impairing the generated power necessary for the operation of the artificial satellite by the solar cell paddle. Objective.

  A solar cell paddle control device according to the present invention includes a satellite body, a solar cell paddle attached to the satellite body, a driving device for rotating the solar cell paddle uniaxially, and a rotation angle command value of the solar cell paddle for the satellite body. A control unit that generates and calculates a rotation angle of the solar cell paddle relative to the satellite body, and controls the driving device so that the rotation angle follows the rotation angle command value, and the control unit is based on the solar cell paddle When power supply is no longer necessary, control the rotation angle to reduce the atmospheric resistance received by the solar battery paddle, determine whether the power balance of the entire satellite is satisfied with charging less than half an orbit, When the overall power balance is established, the solar cell paddle is rotated backward from the rotation angle that reduces atmospheric resistance so that the light receiving surface of the solar cell paddle faces the sun during the required charging time. Or if the total power balance satellite is not satisfied is intended to sequentially rotate the solar arrays.

  The solar cell paddle control device according to the present invention can reduce the on-board propellant by controlling the rotation angle of the solar cell paddle so that the atmospheric resistance is reduced, and can reduce the mass of the entire satellite. It becomes possible.

1 is a perspective view showing a configuration of an artificial satellite according to Embodiment 1. FIG. It is a figure which shows the operation | use form of the conventional paddle control of the artificial satellite by Embodiment 1. FIG. 1 is a configuration diagram of a solar cell paddle control device that reduces atmospheric resistance according to Embodiment 1. FIG. FIG. 3 is a diagram showing a processing flow of a control device for a solar cell paddle for reducing atmospheric resistance according to the first embodiment. FIG. 6 is a diagram illustrating an operation mode of paddle control in the case of forward rotation according to the first embodiment. FIG. 6 is a diagram showing an operational form of paddle control in the case of reverse rotation according to the first embodiment.

Embodiment 1 FIG.
FIG. 1 is a perspective view showing the configuration of an artificial satellite according to Embodiment 1 of the present invention. In the figure, the artificial satellite includes a satellite body 1, an observation sensor and communication antenna 2, a solar cell paddle 3, a paddle driving device 4, and a shunt 5. The observation sensor and the communication antenna 2 are attached to the satellite body 1 with separate observation sensors and communication antennas fixed thereto. The artificial satellite moves in the traveling direction 7.

  The solar cell paddle 3 is supported by the satellite body 1 via the paddle drive device 4 so as to freely rotate around one axis. The paddle drive device 4 is housed inside the satellite body 1. Further, a solar battery cell for generating electric power is attached to one surface of the solar battery paddle 3. The paddle drive device 4 of the solar cell paddle 3 may be, for example, one whose rotating shaft is canted with respect to the traveling direction. Further, the solar cell paddle for the satellite body 1 may be one wing (one) or both wings (two).

  Here, in order to facilitate understanding, a conventional paddle control of an artificial satellite will be described as a comparative example. FIG. 2 is a diagram exemplifying an operation mode of paddle control of a conventional artificial satellite shown as a comparative example. In FIG. 2, the artificial satellite directs the observation sensor 2 attached to the satellite body 1 to the earth 100. The artificial satellite orbits the earth 100 along a circular orbit passing through the satellite orbit plane 6 around the earth 100. In the example of FIG. 2, the artificial satellite moves in the traveling direction 7. Further, an orbital position on the opposite side of the earth 100 with respect to the sun 101 is defined as point A, and points B, C, and D each time the phase advances by 90 ° in the traveling direction 7 with reference to that position. .

  Further, when the artificial satellite is located at point D, the paddle rotation angle at which the light receiving surface of the solar cell paddle 3 faces the sun is defined as 0 °. The direction in which the paddle is rotated so that the light receiving surface of the solar cell paddle 3 always faces the sun is defined as forward rotation, and the opposite direction is defined as reverse rotation.

  In the conventional paddle control, the paddle control is performed so that the light receiving surface of the solar cell paddle always faces the sun, and the solar cell paddle rotates forward at an angular velocity that approximately matches the orbital angular velocity called the clock rate. The sun tracking is controlled. Regardless of the shaded area of the earth, the paddle is rotated to keep track of the sun.

  In addition to the above, conventional paddle control includes hold control for maintaining a constant rotation angle of the solar battery paddle, and through control for rotating the solar battery paddle at the maximum rotation rate that can be output by the paddle drive mechanism.

  In the conventional paddle control, focusing on the atmospheric resistance received by the solar cell paddle, the paddle angles 0 ° and 180 ° at the orbital positions D and B are proportional to the area projected with respect to the traveling direction of the satellite. The atmospheric resistance experienced by the battery paddle is maximized. On the other hand, at the orbital positions A and C, the paddle angles are 90 ° and 270 °, respectively, and the area projected in the traveling direction of the solar cell paddle is minimized, and the atmospheric resistance is also minimized.

  Next, the configuration and operation of the control system of the solar cell paddle 3 with reduced atmospheric resistance according to the first embodiment will be described. FIG. 3 is a diagram showing a configuration of the solar cell paddle control apparatus according to the first embodiment that controls the rotation of the solar cell paddle 3. The solar cell paddle control apparatus according to Embodiment 1 includes a computer (control unit) 10 and a paddle drive circuit 11. The computer 10 is connected to a GPS receiver 15, a star sensor 16, a solar model 17, and a power controller 12. The GPS receiver 15, the star sensor 16, and the power controller 12 are attached to the satellite body 1. The paddle drive circuit 11 is provided inside the paddle drive device 4.

  The computer 10 receives satellite event information 18 from each satellite device mounted on the satellite body 1. The paddle drive circuit 11 rotates the solar cell paddle 3. The solar battery paddle 3 supplies power generated in the solar battery cell to the satellite body 1 through the shunt 4, and the shunt 4 dissipates surplus power. The power controller 12 supplies power to the satellite load 13 and the battery 14 in each satellite device mounted on the artificial satellite. The shunt 4 is connected to the power controller 12. The satellite event information 18 indicates occurrence information of various events such as a mission observation event by the observation sensor 2 mounted on the satellite, a transmission communication processing event of mission observation data, and the attitude maneuver of the satellite body 1.

  In FIG. 3, the GPS receiver 15 observes the GPS signal and measures the orbit position of the artificial satellite. The star sensor 16 measures the attitude angle of the satellite. The solar model 17 calculates the sun direction from the satellite time. Various information is output to the computer 10. Further, the paddle angle instruction value of the solar battery paddle 3 output from the computer 10 is output to the paddle drive circuit 11.

  The paddle drive circuit 11 controls the solar cell paddle 3 to have a predetermined rotation angle based on the paddle angle instruction value from the computer 10. When sunlight is applied to the solar cells of the solar battery paddle 3, power Ps is generated, and the generated power Ps is supplied from the shunt 4 to the power controller 12. The power controller 12 supplies the power Pa via the shunt 4 to the computer 10, the satellite load 13 of the satellite body 1, and the battery 14. The power controller 12 manages the load state of the satellite load 13 and the charge / discharge state of the battery 14. The power controller 12 monitors the power Pl consumed by the satellite load 13, the charge / discharge status of the battery 14 (power obtained by subtracting the current charge power from full charge), and the power generated in the solar cell paddle 3. The power controller 12 obtains the power necessary for charging the battery 14 based on the charge / discharge status of the battery 14, and is necessary for charging the power Pl of the satellite load 13 and the battery 14 from the power Ps generated in the solar cell paddle 3. The surplus power (Ps−Pl−Pb) of the artificial satellite minus the power Pb is calculated. Here, Pa = P1 + Pb. The power controller 12 sends a command to the shunt 4 to dissipate the surplus power in the shunt 4 based on the calculated surplus power of the artificial satellite, and the shunt 4 consumes the power Psh (= Ps−Pa). Control the surplus power of the artificial satellite. Further, the computer 10 is provided with a function of inputting the satellite event information 18 such as the charge / discharge status of the battery 14, the presence / absence of observation equipment, and communication of mission observation data from the power controller 12.

FIG. 4 shows a control algorithm flow of the solar cell paddle 3 for reducing the atmospheric resistance. The determination process 30 is based on a specific orbital position based on the specific orbital position from the charge / discharge status of the battery 14 from the power controller 12 in the computer 10 and the satellite event information 18 such as the presence / absence of use of observation equipment and the transmission of mission data. Estimate the power consumption of the circuit. In addition, based on the estimated power consumption of one round of the future, the generation power time required for the power (discharge power) discharged from the battery 14 of the future round to coincide with the power to be charged (charge power) is Calculate the target value. As a result, the charging time required to satisfy the battery storage / discharge balance for the next orbit of the track is calculated, and whether or not the power balance is established in the charging time when the target value of the power generation time is less than a half cycle of the track. judge.
Note that the power balance is established is a state where the charging power and discharging power of the battery 14 coincide.

  In the determination process 30, when the power balance is established when the target value of the power generation time is less than a half orbit of the orbit, the tracking control / hold control of the solar battery paddle 3 is performed at a predetermined orbit position where the power balance is established. Then, they are coupled by through reverse rotation 31. At this time, control is performed by rotating the solar cell paddle 3 at the maximum drive rate so that the light receiving surface of the solar cell paddle 3 faces the sun.

  On the other hand, in the determination process 30, if the power balance is not established in the charging time when the target value of the power generation time is less than a half orbit of the orbit and it is necessary to generate the power more than a half orbit of the orbit, the determination process 32 further The solar battery paddle 3 is always opposed to the sun during sunshine to determine whether it is necessary to generate electric power. As a result of the determination process 32, when there is no need to generate electric power by always facing the solar cell paddle 3 to the sun during sunshine, tracking control / holding of the solar cell paddle 3 is performed at an orbital position corresponding to the required electric power generation time. These are coupled by through forward rotation control 33.

  Other than that, tracking control and hold control are switched at the boundary of the shade of the earth, and during that time, through forward rotation control 34 is performed. At this time, control is performed by rotating the solar cell paddle 3 at the maximum drive rate so that the light receiving surface of the solar cell paddle 3 faces the sun. At this time, in both cases, when holding the rotation angle of the solar cell paddle 3, the paddle control angle of the solar cell paddle 3 that minimizes the atmospheric resistance is held, and the atmospheric resistance received by the solar cell paddle 3 is reduced.

  The difference between the through forward rotation and the through reverse rotation will be described with reference to the drawings. FIG. 5 shows an operation mode of paddle control of the solar cell paddle 3 in the case of through forward rotation, and FIG. 6 shows an operation mode of paddle control in the case of through reverse rotation.

In FIG. 5, since it is necessary to generate electric power more than half an orbit, the solar cell is changed from a predetermined orbit position between point A and point B to a predetermined orbit position between point D and point A in sunshine. The paddle 3 secures generated power by solar tracking control.
For the trajectory position between D point and B point, the solar paddle 3 is controlled from solar tracking control through through forward rotation control, hold control, through forward rotation control to the trajectory position satisfying the power balance in the computer 10. Finally, control is performed in the order of the original sun tracking control.
At this time, the paddle rotation angle during the paddle hold control is 90 °, and the influence of atmospheric resistance on the solar cell paddle 3 is minimized. Further, the rotation angle through which the solar cell paddle 3 is passed is less than 90 ° in the case of forward rotation, and can be passed in a shorter time than in the case of reverse rotation, leading to a reduction in atmospheric resistance.

  In addition, even when it is necessary to generate power by always facing the solar cell paddle 3 with the sun during sunshine, the boundary of the sunshine / shade is controlled with paddle-through forward rotation control and the sun to reduce atmospheric resistance during the shade. It is possible to reduce the atmospheric resistance received by the solar cell paddle 3 by setting the track position for switching the tracking control.

On the other hand, in FIG. 6, since the power balance is established when the power generation time is less than a half orbit of the orbit, the atmospheric resistance received by the solar cell paddle 3 between the point D and the point B is independent of the power generation. The rotation angle of the solar cell paddle 3 is maintained by paddle hold control so as to minimize.
Further, from point B to point D, the solar battery paddle 3 is controlled in the order of hold control, through reverse rotation control, solar tracking control, through reverse rotation control, and hold control with respect to the orbital position that establishes the power balance. Then, the generated power is obtained during solar tracking control.
In this case, the paddle rotation angle during the paddle hold control is 270 °. Further, the rotation angle through which the solar cell paddle 3 is passed is less than 90 ° in the case of reverse rotation, and it is possible to pass through in a shorter time than in the case of through-forward rotation.

  The paddle control for reducing atmospheric resistance according to the first embodiment estimates the power consumption of one round of the future from the satellite event information, and the paddle of the solar cell paddle 3 to ensure the necessary generated power. Control is planned. For this reason, the power balance of the satellite is always established. The present invention is also applicable to the case where tracking control is performed so that the solar cell paddle 3 always faces the sun during sunshine. In addition, the on-board propellant can be reduced by reducing atmospheric resistance, the mass of the entire satellite can be reduced, and the mission period of the artificial satellite can be extended. In addition, since orbital descent due to atmospheric resistance is reduced, it is possible to maintain the orbit with high accuracy.

  As described above, the solar cell paddle control apparatus according to the first embodiment includes the satellite body 1, the solar cell paddle 3 attached to the satellite body 1, the drive device 4 for rotating the solar cell paddle 3 uniaxially, A rotation angle command value of the solar cell paddle 3 for the satellite body 1 is generated, a rotation angle of the solar cell paddle 3 for the satellite body 1 is calculated, and the driving device 4 is controlled so that the rotation angle follows the rotation angle command value. The computer (control unit) 10 controls the rotation angle to reduce the atmospheric resistance received by the solar cell paddle 3 when the power supply by the solar cell paddle 3 is not required. Further, it is determined whether or not the power balance of the entire satellite is established by charging less than half of the orbit, and if the power balance of the entire satellite is established, the light receiving surface of the solar cell paddle 3 is solar When Rotated in reverse solar wing 3 from the rotation angle to reduce the air resistance as against, characterized in that.

  The computer (control unit) 10 includes a GPS receiver 15 for determining the orbital position of the satellite, a computer (control unit) 10 that calculates the solar direction with respect to the inertial system from the satellite time information, and an attitude angle with respect to the inertial system. Based on the star sensor 16 that detects the sun, the sun direction relative to the satellite coordinate system is calculated, and the rotation angle that reversely rotates the solar cell paddle 3 from the angle formed by the calculated solar direction and the normal line of the light receiving surface of the solar cell paddle 3 Is calculated.

  Further, the computer (control unit) 10 calculates the power consumption of the satellite event per one orbit of the next orbit based on the specific orbit position, and stores the battery 14 in the next orbit of the next orbit based on the calculated power consumption. A charging period necessary to satisfy the discharge balance is calculated, and the solar battery paddle 3 is rotated so that the light receiving surface of the solar battery paddle faces the sun during the charging period. The rotation angle is maintained so as to minimize the atmospheric resistance received by 3 and the rotation angle command value is set so that the solar cell paddle 3 is rotated at the maximum drive rate during the two periods.

  Thereby, it is possible to reduce the propellant on board and reduce the mass of the entire artificial satellite by reducing the atmospheric resistance. Alternatively, the mission period of the artificial satellite can be extended. Furthermore, since orbital descent due to atmospheric resistance is reduced, it is possible to maintain the orbit with high accuracy.

  DESCRIPTION OF SYMBOLS 1 Satellite body, 2 Observation sensor, 3 Solar cell paddle, 4 Paddle drive device, 5 Shunt, 6 Satellite orbital plane, 7 Traveling direction, 10 Computer (control part), 11 Paddle drive circuit, 12 Power controller, 13 Satellite load , 14 battery, 15 GPS receiver, 16 star sensor, 17 solar model, 18 satellite event information, 30 determination unit processing, 31 paddle through reverse rotation control, 32 determination processing, 33 paddle through forward rotation (switched at requested position), 34 Paddle-through forward rotation (switches at the border of sunshine and shade), 100 Earth, 101 Sun.

Claims (3)

The satellite body,
A solar cell paddle attached to the satellite body,
A driving device for rotating the solar cell paddle uniaxially;
A control unit that generates a rotation angle command value of the solar battery paddle for the satellite body, calculates a rotation angle of the solar battery paddle for the satellite body, and controls the driving device so that the rotation angle follows the rotation angle command value;
With
When the power supply by the solar cell paddle is no longer necessary, the control unit controls the rotation angle to reduce the atmospheric resistance received by the solar cell paddle, and further, the power balance of the entire satellite is established by charging less than half an orbit If the power balance of the entire satellite is established, the solar battery paddle is removed from the rotation angle that reduces the atmospheric resistance so that the light receiving surface of the solar battery paddle faces the sun during the required charging time. Reverse rotation or if the power balance of the entire satellite is not established, rotate the solar cell paddle forward,
Solar cell paddle control device.   The control unit includes satellite coordinates based on a GPS receiver for determining the orbital position of the satellite, a calculator for calculating the sun direction with respect to the inertial system from the satellite time information, and a star sensor for detecting an attitude angle with respect to the inertial system. The solar cell paddle control device according to claim 1, wherein a solar direction with respect to the system is calculated, and a rotation angle for reversely rotating the solar cell paddle is calculated from an angle formed by the calculated solar direction and a normal line of the light receiving surface of the solar cell paddle. In order to satisfy the battery storage / discharge balance of the next orbit of the next orbit based on the calculated power consumption, the control unit calculates the power consumption of the satellite event per one orbit of the next orbit based on the specific orbit position. Calculate the required charging period,
During the charging period, the solar cell paddle is rotated so that the light receiving surface of the solar cell paddle faces the sun,
2. The artificial satellite according to claim 1, wherein the rotation angle command value is set so as to maintain the rotation angle so as to minimize the atmospheric resistance received by the solar battery paddle during a period other than the charging period.

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