JPS6211167Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of a shunt device that stabilizes the output voltage of a solar battery power source used in an artificial satellite.

Solar cells are often used as a power source for artificial satellites. In this case, it is well known that a shunt circuit is used to make the power generated by the solar cell a constant voltage and supply it to the onboard equipment. As shown in Figure 1, this is achieved by dividing the surplus power of the solar cell array into shunt circuits 3a, 3b, and 3c consisting of a combination of a resistor _R and a transistor Tr, so that a constant voltage is always supplied to the load. This is a method of supplying electricity.

In FIG. 1, 1 and 2 are solar cell arrays formed by electrically connecting a plurality of solar cells; 3a and 3;
Shunt circuits b and 3c are provided at the output ends of the solar cell arrays 1 and 2, respectively, and are composed of a resistor R and a transistor T _r . 4 is a storage battery heater, 5 is a storage battery, 6 is a storage battery charging circuit, 7 is an error voltage detection circuit, 8 is a shunt drive circuit, 9 is a storage battery heater control circuit, 10
is a regulated bus line (power supply supplied to the load), and r ₁ and r ₂ are dividing resistors.

Since the conventional shunt device is configured as described above, the voltage of the electric power generated in the solar cell arrays 1 and 2 is detected by the dividing resistors r ₁ and r ₂ , and
In the error voltage detection circuit 7, an error output proportional to the difference from a constant voltage is generated. This error output is transmitted to the shunt drive circuit 8 by the transistors T constituting each shunt circuit 3a, 3b, 3c.
It is amplified and distributed to the base drive output of _r . As a result, the current in the solar cell array 2 is reduced to the shunt circuit 3.
a, 3b, and 3c, the voltage decreases according to the characteristics of the solar cell, and the sum of the voltages with the solar cell array 1 is always maintained at a constant voltage. In addition, the heater control circuit 9 is connected to the thermistor T of the storage battery 5.
This device detects the temperature, and when the temperature falls below a certain level, it supplies power to the heater 4 to maintain the temperature above the certain level.

By the way, these shunt circuits 3a, 3b, 3c
Surplus electricity flows into the spacecraft, where it is converted into heat and finally released into space.In order to handle this heat generation in normal artificial satellites, a lot of care is taken to install the shunt circuit. In particular, various designs and calculations must be made to ensure that the thermal balance is not disturbed.

On the other hand, a storage battery 5 is mounted on the satellite as a power source when the satellite is in the shade.When discharging in the shade, it generates heat and the temperature decreases relatively little. When charging with energy, the temperature of the storage battery 5 decreases due to an endothermic reaction accompanying charging, and may fall below its usage limit. In addition, a heater 4 is attached to the storage battery 5, and when the temperature becomes low, the heater 4 is normally turned on to keep the battery warm. However, when the capacity of the storage battery 5 increases, the power required for the heater 4 increases, and since it is supplied from the voltage-stabilized bus line, some power is lost in the shunt circuits 3a, 3b, and 3c. Furthermore, electric power was required for the heater 4, and the electric power generated by the solar cell arrays 1 and 2 had to have a considerable margin. This has a negative impact on the satellite in terms of cost, weight, etc. due to the increase in the number of solar cells.

In order to eliminate these wastes, this invention provides a shunt device that directs shunt power to the power of the storage battery heater and operates as a normal shunt circuit even when the storage battery heater is not needed.

An embodiment of this invention will be described below with reference to the drawings.

In Figure 2, 1 and 2 are solar cell arrays, 3
a and 3b are normal shunt circuits, 3c is a shunt circuit that also serves as a storage battery heater, which is a feature of this invention, 5 is a storage battery, and shunt circuits 3a, 3b, 3c
The operating signal for the signal is supplied by the error voltage detection circuit 7 and the shunt drive circuit 8. This shunt drive circuit 8 includes a drive circuit 11 for shunt circuits 3a and 3b and a drive circuit 12 for shunt circuit 3c.
It consists of an AND circuit 13.

As a command signal for the drive circuit 12, the output of the storage battery temperature monitor circuit 9 (low temperature limit value, e.g. 0°C
(When the temperature reaches the low temperature limit, an H level signal is output) and the output of the error amplifier 7 are ANDed by the AND circuit 13. When the temperature of the storage battery 5 falls below the low temperature limit, a certain level of power is sent to the shunt circuit 3c. By adding heat and generating heat, the temperature of the storage battery 5 is maintained at a predetermined temperature. Note 6
1 is a storage battery charging circuit, and 10 is a constant voltage bus line.

By the way, when the temperature of the storage battery 5 rises, the output of the temperature monitor circuit 9 becomes L level, and the shunt circuit 3c no longer generates heat.

As described above, this invention uses the shunt circuit 3c shown in Fig. 2, which also serves as a heater, instead of the storage battery heater shown in Fig. 1, and thereby serves both as a constant voltage for the solar cell array and as a heater for the storage battery. This makes it possible to use electricity effectively. The power of a typical storage battery heater is about 10W, and two or more storage batteries are usually mounted on a satellite, so it is possible to save power by at least 20W.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a conventional shunt device, and FIG. 2 is a block diagram of a shunt device showing an embodiment of this invention. In the figure, 1 and 2 are solar cell arrays, 3a and 3
b, 3c are shunt circuits, 5 is a storage battery, 6 is a charging circuit, 7 is an error voltage detection circuit, 8 is a shunt drive circuit, 9 is a storage battery temperature monitor circuit, 10 is a bus line, 11 and 12 are shunt drive circuit sections, 13 is
It is an AND circuit. Note that the same or corresponding parts in the figures are indicated by the same reference numerals.

Claims (1)

[Scope of utility model registration request] a solar cell array formed by electrically connecting a plurality of solar cells; a storage battery for charging electrical energy generated from the solar cell array; and a plurality of shunt circuits connected to output terminals of the solar cell array; An error voltage detection circuit detects the output voltage of the solar cell array, and a current flowing from the solar cell array to the shunt circuit is controlled by the output voltage of the error voltage detection circuit to keep the output voltage of the solar cell array constant. and a monitor circuit that monitors the temperature near the storage battery,
The output of this monitor circuit and the output of the error voltage detection circuit operate a predetermined shunt circuit among the plurality of shunt circuits, and the heat generated from the shunt circuit is used to maintain the storage battery at a predetermined temperature. A shunt device characterized by: