JPS6295617A - Electric power unit for artifitial satellite - Google Patents

Abstract

PURPOSE:To decrease the number of both solar battery strings and shunt circuits by changing the number of solar batteries set in parallel of the solar battery strings for each string and in steps of binary exponents. CONSTITUTION:A solar battery paddle 3 contains solar battery strings 1a-1c connected in parallel with each other and a binary exponent ratio is secured for the number of solar batteries set in parallel of each battery string. The gate turn-off SCR 9a-9c are used to shunt those strings 1a-1c respectively and a solar battery array output 10 is used as a power supply to turn on these SCR. While an independent solar battery string 11 for gate-off is connected to the return side of the array 3 as a power supply to turn off the SCR. Thus the power supply output 12 is obtained and compared with the output voltage of the array 3 and an error signal obtained from this comparison is supplied to a shunt logic circuit 13. Then a signal is delivered to instruct a specific solar battery string to be shunted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a power supply device for an artificial satellite that obtains electric power by connecting a solar cell array to the main body of the artificial satellite.

[Conventional technology]

FIG. 2 is a diagram showing an example of a conventional device for controlling the output of a solar cell array to a DC voltage within a certain range. The output ends of the solar cell strings (1a), (1b), and (1c) are combined using backflow prevention diodes (2aX2t) The current flowing through the shunt circuit (6) is changed by the output of the error amplifier (5) to control the power supply voltage (7).

In other words, in Fig. 2, (1a), (1b), and (1c) are solar cell strings? (2aX21:+X2C) is a backflow prevention diode.

(3) is a solar cell array, (4) is a slip ring for constantly connecting the solar cell array (3) pointing toward the sun and the satellite body, and (5) is an error amplifier.

(6) is a shunt circuit, and (7) is an output voltage. The conventional artificial #star'dL source device is a solar cell string (1a
) (tb) (1c) connected in parallel (3
) and the solar cell output voltage decrease by increasing the load current of the solar cell, an error amplifier (5) and a shunt circuit (6)
The shunt circuit (6) is connected from the solar cell array (3) so that the output voltage (7) is at a certain value or below a certain value.
) is configured to increase or decrease the 1L flow that bypasses the output voltage (7) in FIG. 2 and controls the output voltage (7) within a certain range.

As the power generated by the solar cell array becomes larger, this power supply device IT is equipped with "shunt voltage" (output voltage of the solar cell array) and "shunt current" (shunt circuit).
6), that is, the shunt capacity increases, making it difficult not only to design the circuit but also to control the heat, making it impractical.An example of an improved device shown in FIG. 3 is also available.

The device in Figure 3 has multiple shunt circuits (<!aX6b)
(6c), solar cell strings (1a) and (1), respectively.
b) Connect in parallel to (1c) and connect the shunt drive circuit (aeL
) (8b) (8c), the output voltage ( 7) within a certain voltage range, and shunt circuit (/a) G6bX
This is a configuration that reduces the total amount of power consumed in step 6c).

That is, in Figure 3, (1a) (1b) (1c
) is the solar cell string l (2a) (Zb) (2c)
(backflow prevention and solar cells) IJing (1a) (1b
) (1c), (3) is a solar cell array consisting of a plurality of solar cell strings (1a) (1b) (1c), (4) is a solar cell string (
1a) A slip ring that connects (1b) and (1c).

(5) is an error amplification device that detects and increases the error of the output voltage (7) from the desired range, (6aX6bX6c)
are shunt circuits corresponding to the solar cell strings (1a), (1b), and (1c), and (7) is the power supply output voltage 1 (8a
X8bX8c) is a shunt circuit (6a) when the output signal of error amplification (5) exceeds a predetermined level.
This is a shunt drive circuit that drives X61) and X6c).

The device shown in Fig. 3 has three shunt circuits (
6aX6t)
6b
Each shunt drive circuit (aaXFJbX8c) operates within an individual operating range associated with the output signal of
When the error signal is larger than the operating range of , the impedance of the shunt circuits (6a) (6b) (6c) is made sufficiently low.

In other words, as the output signal of the error amplifier (5) increases,
First, the impedance of the shunt circuit (mu), which the shunt drive circuit (6a) enters into the operating range, gradually decreases from a very large value, but the shunt drive circuit (8b) and the shunt drive circuit (8c) do not operate yet. Shunt circuit (6b
) and the shunt circuit (6c) remain very large, so the output of the solar cell array (3) is mainly the solar cell string (1b) and (
1c), which will be supplied to the load. Next, when the output voltage of the error amplifier (5) exceeds the operating range of the shunt drive circuit (8b), the shunt drive circuit (8b)
The impedance of the shunt circuit (6b), which enters the operating range, gradually decreases from a very large value.

At this time, the shunt drive circuit (8c) does not operate.

On the other hand, since the impedance of the shunt circuit (6a) is sufficiently low, all the output current of the solar cell string (1a) flows through the shunt circuit (/A), and the output voltage of the solar cell string (1a) is very low. Therefore, the amount of heat generated by the shunt circuit (6a) is small.

[Problem that the invention seeks to solve]

In this way, shunt d moving path (8a) (8b) (8c)
operate in sequence in response to the output signal of the error amplifier (5),
The output signal of the error amplifier (5) is transmitted to the shunt drive circuit (8a
) (8'b) (8c), the capacitance of the shunt circuit can be reduced using the first method by making sure that the impedance of the corresponding shunt circuit (6a) (Sb) (6c) is sufficiently low. This reduces the amount of heat generated by the shunt circuit due to variations in the load on the power supply, thereby reducing the drawbacks of the first method. However, as shown in FIG. 3, this second method requires a slip ring contact for each IJ song output, and a shunt drive circuit must be provided for each shunt circuit. Especially when the number of parallel strings increases, this becomes a significant drawback. In addition, in order to reduce the number of slip ring contact capacitances, shunt circuits C6e, )C6
bX6c) and shunt drive circuit (8a) (8b) (8
Although it is possible to place c) on the solar cell array side, the shunt drive circuit includes at least a reference voltage generation circuit and a circuit for amplifying the error amplifier output signal and the reference voltage by a ratio e, both of which are generally subject to temperature changes. Even though it is sensitive to solar cell arrays, it must be deposited, for example, on the thick battery paddle in outer space of the satellite body.
The operating conditions for these circuits are severe and the circuit design is therefore complex. Furthermore, the mechanical holding mechanism for attaching these electronic circuits to the solar cell array is also difficult.

[Means for solving problems]

This invention was made in order to improve such conventional problems, and the number of parallel solar cells in a solar cell string is changed step by step in a binary exponential manner for each solar cell string. The aim is to reduce the number.

[Effect]

Solar cells) The number of parallel solar cells that make up the IJ song can be doubled, quadrupled, eight times, etc. for each solar cell string.
A solar cell array is constructed from a plurality of solar cell strings, so if the solar cell strings are digitally shunted, the shunt resolution will be the minimum number of solar cells in parallel.) While securing the IJ song, The shunt can be increased by reducing the number of solar cell strings.

[Actual 78i Example] Figure 1 is a block diagram of the satellite power supply device according to the present invention. In the drawing, (Ia), (1b), and (Ic) are solar cells. diodes for parallel connection, (3) is a solar cell array in which solar cell strings (1a) (1b) (1c) are connected in parallel, (4) is a slip ring, (5)
) is an error amplifier that compares the output voltage (7) with the reference voltage and amplifies the difference voltage = (5'X9bX9C) is the gate turn-off corresponding to the solar cell string (1a) (1b) (Ia) 80 R , (13 is a shunt logic circuit that derives a signal to the solar cell array side so that the output voltage (7) is within a predetermined voltage range based on the output signal of the error amplifier (5), 14) is a shunt control circuit for controlling the gate turn-off lllOR corresponding to the string to be shunted based on the signal of the shunt logic circuit αKEN, and a!9 is a shunt logic circuit (from 13, which commands the string to be shunted). The signal αG is a capacitor bank for smoothing the output voltage.

First, considering the case where the load on this power supply is light, the output voltage will be higher than the predetermined voltage when closed-loop control is not performed due to the nonlinear characteristics of the solar cell, and the error amplifier (5) will be connected to the solar cell. An error signal is generated that shunts one or more of the strings.

By the way, solar cell strings (1a) (1b) (1c
), in this example, in a binary exponential manner, i.e. solar cells) IJ song 1a) (1b) (1a)
The ratio of the number of parallel solar cells constituting is 2°=1.2
The case where '=2.2'=4 will be explained. (In this example, since there are three solar cell strings, the number of parallel solar cells in solar cell strings (1a), (1b, and 1a) is set at a ratio of 1:2:4, but the solar cell strings are 1:2:4.) When the number of ridges is N, the ratio of these parallel solar cells is approximately 2G, 21.22.・・・・・・・・・・・・2
Assuming N-1, the error signal when the load on the power supply device is light as described above is converted to a digital signal or a logic symbol signal and is sent to the shunt control circuit via the slip ring (4). It is derived from I. In the shunt control circuit I, the solar cell string to be shunted is
1a) (1b) (1c) and turns off the corresponding SCR of gate turn-off 80R (9a) (?b) (9c) to shunt the solar cell string. However, since the load is light, for example, turn on the gate turn-off BOR (turtle) of the solar cell string (1a), and if there is still an error voltage, turn on the solar cell string (1b). Short circuit, and if there is still an error voltage, short-circuit the solar cell string (Ia) (1b), and if there is an error voltage, then (IC), then (1a) and (1b).
1c) + (1b) and (IC) I Finally (1a)
(1b) and (1C), and the output voltage (power) is controlled within a constant voltage range so as not to generate an error voltage.On the other hand, when the load on this power supply device is heavy ( When this happens, the output of the error amplifier (5) becomes a signal level that reduces the number of solar cell strings to be shunted, and the shunt logic circuit αJ outputs a logic signal level that reduces the shunt state of the solar cell strings. 9 to the shunt control circuit I via the slip ring (4).Furthermore, in the shunt control circuit α4, for example, the current (1c)
If only the solar cell string (1c) is shunted, the shuntler of the solar cell string (1c) is released.

Controlling the corresponding gate turn-on SCR to reduce the one-step shunt condition to 7 yand the solar cell strings (1a) and (1b), still output voltage (7)
When the voltage is lower than the specified value, the gate turn SCR is sequentially controlled so that only the solar cell string (1b) is shunted, and the shunt state is further reduced by one step. At this time, in order to turn off the gate turn-off SCR to release the shunt from the solar cell string in the shunt state, the power output (obtained by connecting an independent gate-off solar cell array αυ to the return side of the solar cell paddle (3) I3 to S
This is done by connecting to the gate of CR.

As described above, this invention is developed by connecting the solar battery paddle (3) in parallel with the multiple solar battery strings (1a), (1b), and (1c), and the parallel solar battery of each solar battery string. The ridges are configured to have a binary finger ridge ratio, and the solar cell strings (1a) (1
b) Gate turn-off s to shunt (1c)
(Use 3R(9a)(9b)(9c) and its sc
The above solar cell array output (II) is used as the power source for turning on R, and the independent gate-off operator V# is connected to the pond string αυ on the return side of the solar cell paddle as the power source for turning off. Source output output α2
Furthermore, compared with the output voltage of the solar battery paddle (3),
The error signal is converted by the shunt logic circuit α into a signal for instructing which solar cell string to shunt or a signal for increasing or decreasing the number of strings to be shunted, and the digital signal is derived to the solar cell paddle side. Based on this digital signal, which is logically decoded by the shunt control circuit U, the solar cell array output α1 and the gate-off solar cell array output are connected to the gate turn-off SOR (9a) (9b) connected to the solar cell string.
By switching the application to the gate of (9c), the SCR
is turned on and off to control the shunt state of the solar battery paddle, and the output voltage (7) of the solar battery paddle is controlled within the - range.

In the above embodiment, an example of a structure in which there are three solar cell arrays has been described, but there is no limit to this number, and by increasing the number of solar cell strings, the change in output voltage can be controlled to be significantly smaller.

〔Effect of the invention〕

As described above, the satellite-source device according to the present invention requires fewer solar cell strings.

By simply shunting them digitally, the change in output voltage can be reduced, and the circuit for shunting the solar cell array can be made extremely simple. It is easy to attach it outside the body.

Furthermore, the xi of the satellite can be reduced by reducing the number of slip ring contact capacitances, and the 5Tf4B can be mounted with good resistance to interference noise by digitizing control signals. In addition, this invention makes it possible to reduce the size and weight of the circuit required for the shunt function, which greatly contributes to the reduction in the size of solar battery paddles and the simplification of S construction.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of a power supply device for an artificial satellite according to the present invention, and FIGS.
! FIG. 2 is a diagram for explaining a power source device. In the figure, I (1aX1bXIC) is the solar cell)
IJ ng. (2a) (2b) (2c) C backflow prevention diode, (3
) is a solar array, (4) is a slip ring, (5) is
is an error magnifier. (6) is the shunt circuit t (8a) (8b) (8c) is the shunt drive circuit I C9&)C9b)C9a) is the gate turn-off 80 R, Ql) is the solar cell array for gate turn-off, Ql is the shunt logic circuit, ( +4 is a shunt control circuit, and σe is a capacitor bank. In the figure, the same or corresponding parts are denoted by the same reference numerals.

Claims (1)

[Claims] A solar cell array consisting of a plurality of parallel-connected solar cell strings each electrically combining a plurality of solar cells is connected to the satellite body, and by shunting each of the solar cell strings, the solar cell array is In a satellite power supply device configured to maintain a constant output voltage,
a solar cell array in which the number of parallel solar cells constituting the solar cell string is arranged in a binary exponential manner for each of the solar cell strings; and a plurality of gate turn-off SCRs connected to each of the solar cell strings in correspondence with each other; , an error amplifier that compares the output voltage of the solar cell array with a reference voltage and a power supply connected to the return side of the solar cell array, and amplifies the difference voltage; and a solar cell that shunts the output signal of the error amplifier. Applying the output of the solar cell array or the power supply to the gates of the plurality of gate turn-off SCRs to turn on and off the plurality of gate turn-off SCRs based on the output signal of the shunt logic circuit that converts the string into a signal indicating the string. A power supply device for an artificial satellite, comprising a control circuit for controlling the satellite.