JPH10209480A - Temperature controlled constant power type solar battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control the current-voltage characteristics and power of the entire solar battery constantly by extracting one solar cell arbitrary from each module and collecting them at one place and then performing small scale concentrated temperature control only for those solar cell extracted depending on the load power/voltage of a satellite. SOLUTION: C11 , C21 ,..., CM1 , C12 , C22 ,..., CM2 and CN1 , C2 N,..., CMN represent solar cells. N solar cells of C11 , C21 ,..., CM1 are connected in series to produce a solar cell module (i) and a solar battery is formed by connecting i(=N) solar cell module in parallel. CG is a solar cell group comprising N solar cells CM1 , CM2 ,..., CMN extracted from each solar cell module arbitrarily for the purpose of temperature control. CNT is a temperature control circuit comprising a temperature sensor for detecting the temperature of the CG and a heater for heating a cell group CG to be controlled at a constant temperature depending on the output from the temperature sensor wherein the value of N is set for the CG group and the current-voltage characteristics and power of the entire solar battery is controlled constantly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solar cell device,
In particular, the present invention relates to a solar cell device mounted on a satellite as a primary power source.

[0002]

2. Description of the Related Art Solar cells are generally used as primary power sources for artificial satellites. However, in a severe space environment in which environmental conditions change greatly, the power generated by the solar cell cannot be used as it is as a power source for an artificial satellite due to a significant change in the characteristics of the solar cell.

Conventionally, in order to supply a stable power / voltage to an artificial satellite, the power / voltage is stabilized by stabilizing the power / voltage by a regulator or by surplus power consumption by a shunt dessipator. Stable power /
The voltage was being supplied. For this reason, it was necessary to mount a regulator or a shunt desipator.

[0004] However, this conventional technique causes difficulty in heat exhaust design due to heat being concentrated at one location, and increases in weight and volume, and poses a great obstacle in thermal design and miniaturization and weight reduction of an artificial satellite. Had become.

FIGS. 3 (a) and 3 (b) are block diagrams showing a conventional technique. FIG. 3 (a) uses a regulator to stabilize the power / voltage supplied to a load L of a satellite. (B) is a block diagram in the case of using a shunt desicipator having a function of consuming surplus power in order to stabilize the power / voltage supplied to the artificial satellite. It is.

In FIGS. 3A and 3B, SA is a solar cell, BAT is a battery, CHG is a BAT charge control circuit, and REG is a regulator. D ₁ , D
₂ is a blocking diode, L is a satellite load, S
HNT indicates a shunt dessipator, respectively.

[0007]

As described above, the conventional problem is that a solar cell is generally used as a primary power source of an artificial satellite. The power cannot be supplied to the satellite, and once the power is stabilized by a regulator for stabilizing the power supplied to the satellite or a shunt desipator for excess power consumption,
It was necessary to supply satellites. For this reason, it is required to mount a regulator and a shunt desiperator, and this has been an obstacle to the exhaust heat design and the reduction in size and weight of the satellite.

[0008] The reason is that, usually, when a solar cell is mounted on an artificial satellite, the current-voltage characteristics and generated power of the solar cell are greatly increased because the solar cell is used in a severe space environment where environmental conditions change greatly. fluctuate. For this reason, if it is attempted to supply the generated power of the solar cell to the artificial satellite as it is, the supplied power and the voltage may fluctuate greatly, and the mounted device may not operate normally.

[0009]

SUMMARY OF THE INVENTION As described above, when a solar cell is mounted on a satellite as a primary power source in a space environment where environmental conditions change greatly, as described above, the solar cell mounted on the satellite is Since the current-voltage characteristics and the generated power fluctuate significantly, a power stabilizing regulator or a surplus power shunt desicipator has conventionally been required for the purpose of stabilizing the power / voltage supplied to the artificial satellite. For this reason, the mounting of the regulator and the shunt desipator has been an obstacle to the heat exhaust design and the small and lightweight design of the satellite.

The present invention has been made in view of the above circumstances, and has been made to solve the above-mentioned problems inherent in the prior art. Therefore, an object of the present invention is to provide a solar cell having excellent characteristics even in a severe space environment. To provide a new solar cell device that eliminates the need for regulators and shunt desipators that were required in the past, and that facilitates the design of artificial satellites for heat removal and miniaturization and weight reduction. is there.

[0011]

In order to achieve the above object, a solar cell device according to the present invention has a structure in which a module in which solar cells are connected in series to a required voltage value is connected in parallel to a required power. One solar cell is arbitrarily extracted from each module in which battery cells are connected in series, collected at one location, and only the solar cells extracted according to the load power / voltage of the satellite need to be intensive and small-scale. Temperature control is performed to stabilize the current-voltage characteristics and generated power of the entire solar cell.

Thus, even in a severe space environment in which environmental conditions change greatly, the current-voltage characteristics and power of the entire solar cell can be stabilized, and a regulator and a shunt desipator, which have been conventionally required, are not used. In addition, it has a function of supplying the stable power of the solar cell directly to the artificial satellite.

[0013]

Generally, a solar cell mounted on an artificial satellite is constructed by connecting solar cells in series up to the voltage required by the artificial satellite to form one module, and connecting the modules in parallel up to the required power.

Further, the solar cell controls the current-voltage characteristics of any one of the series-connected solar cells, so that the current-voltage characteristics of the other series solar cells are the same. It has the characteristic that it is limited to the characteristic.

The solar cell of the present invention utilizes this characteristic to arbitrarily extract one solar cell from each module, collect it at one location, and extract it according to the load power / voltage of the satellite. By performing intensive and small-scale temperature control of only the cells, the current-voltage characteristics and the power of the entire solar cell can be controlled to be constant.

By this means according to the present invention, the control of the solar cell output can be performed centrally and in a small scale at one place, and the regulator and shunt desipator conventionally required are not required, and the generation of the solar cell is eliminated. Power can be supplied directly to the satellite as stable power / voltage.

[0017]

Next, a preferred embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention.

Referring to FIG. 1, C ₁₁ , C ₂₁ ,...
_.. , C _M1 , C ₁₂ , C ₂₂ ,..., C _M2 ,.
.., C _1N , C _2N ,..., C _MN are solar cells. C _1i , C _2i ,..., C _Mi solar cell modules (i) in which M (M is a positive integer) solar cells are connected in series from i = 1 to N (N is a positive integer) It is assumed that the entire solar cell is configured by parallel connection up to ()).

CG is a control target solar cell comprising N solar cells C _M1 , C _M2 ,..., C _MN arbitrarily extracted one by one from each solar cell module for temperature control. It is a cell group. D ₁ , D ₂ ,..., _DN are blocking diodes. CNT is a control circuit for temperature control. The temperature control circuit CNT includes, for example, a temperature sensor that detects the temperature of the control target solar cell group CG, and a heater that controls the temperature of the control target solar cell group CG to be constant according to the temperature sensor detection output. Can be easily configured. BAT is a battery, which is necessary to keep supplying power to the artificial satellite even when there is no power generated by the solar cell in the shade. CHG is a charge control circuit for charging the battery BAT. D ₀ is a blocking diode for discharging the battery BAT. L is the load on the satellite.

FIG. 2 is a graph showing current-voltage characteristics of the solar cell according to the present invention. C ₁ , C ₂ and C ₃ are current-voltage characteristics of a conventional solar cell. _CL is the load curve of the satellite. P _1, P _2, P _3, the current when the load curve of the satellites of C _L - an operating point on the voltage characteristic _{C 1, C 2, C 3} . P ₁ ′, P ₁ ″, P ₂ ′, P ₂ ″, P
₃ ′, P ₃ ″ represent C ₁ , C ₂ ,
Current to C ₃ - is the maximum power point voltage characteristics. V
₁ , V ₂ and V ₃ are voltage values at operating points P ₁ , P ₂ and P ₃ , and I ₁ , I ₂ and I ₃ are current-voltage characteristics C ₁ , C ₂ ,
The current values I ₁ ′, I ₂ ′, and I ₃ ′ in the constant current region of C ₃ are the current values at the operating points P ₁ , P ₂ , P ₃ , P _L , V _L ,
I _L is the operating point on the load curve C _L to be maintained by the control of a solar cell according to the present invention, a voltage value, a current value.

Next, the operation of the embodiment of the present invention will be described with reference to the drawings.

Generally, a conventional solar cell has current-voltage characteristics C ₁ , C ₂ , and C ₃ shown in FIG. The reason why the characteristics do not become constant and fluctuate like C ₁ , C ₂ and C ₃ is that
This is because environmental conditions change. Especially in severe space environment, this fluctuation is large. Therefore, the load curve as the satellite C _L (since normal constant-power characteristic becomes hyperbolic)
, The operating points are P ₁ and P depending on the environmental conditions.
Vary between _2, P _3. For this purpose, the bus voltage V _BUS supplied to the satellite is as follows.

V ₃ = ≦ V _BUS ≦ V _{1 In a} severe space environment, this voltage width becomes very large. Therefore, when supplying to an artificial satellite, as described above, the voltage is controlled by the regulator and the shunt desipator. Must be supplied after being stabilized.

Next, the case where the solar cell according to the present invention is used will be described.

As shown in FIG. 2, the current-voltage characteristics of the conventional solar cell due to changes in environmental conditions are represented by C ₁ , C ₂ , C ₃
It fluctuates like With the solar cell of the present invention, the operating point on the load curve C _{L of the} satellite is stabilized at P _L , and the supply voltage / current is maintained at V _L , I _L. At this time, the supply voltage V _L is previously set to be lower than the operation voltage V _{3 in} the case of C ₃ where the operation voltage on the current-voltage characteristic is the lowest due to environmental conditions, that is, V _L <V _3. The N value of the control target solar cell group CG including the plurality of solar cells is set in advance.

With respect to the temperature control of the control target solar cell group CG including N solar cells, the control circuit CNT detects the supply voltage _VBUS to the artificial satellite and satisfies the following condition. The temperature of the battery cell group CG is controlled.

[0028]

[0029] At this time, the current of the conventional solar cell - the voltage characteristic is assumed to be a C _1, but the operating point is the supply voltage to the P ₁ becomes the load attempts to rise to V _1, as described above V _BUS = V ₁ > V _L , the current-voltage characteristics of N solar cells have a current value in a constant current region = I _L-
The temperature is controlled so as to have a voltage characteristic. At this time, the current-voltage characteristic of each of the solar cell modules (1) to (N) is also adjusted to the current value of the constant current region = I according to the extracted cell characteristic.
_The current-voltage characteristics are controlled to _L. Thus, the entire solar cell, the current value of the constant current region = I _L of the current - voltage characteristics I _L -P ₁ 'is controlled to -P ₁ ", the voltage by the operating point is maintained at P _L is V _L Is stabilized.

Similarly, when the current-voltage characteristics of the conventional solar cell are C ₂ and C ₃ , V _BUS = V ₂ or V
₃ > V _L , the temperature of the N solar cells is controlled so that the entire solar cell has a current-voltage characteristic I _L −P ₂ ′ −P ₂ ″ of a current value in the constant current region = I _L or I _L- P
₃ 'is controlled to -P ₃ ", the voltage is stabilized to V _L.

Next, the case where V ₃ <V _L <V ₂ is considered. At this time, the current-voltage characteristics of the conventional solar cell are V _BUS = V ₁ or V ₂ > V _L for C ₁ and C ₂ , and the current of the entire solar cell is controlled by controlling the temperature of the N solar cells. - voltage characteristics I _L -P ₁ '-P ₁ "or I _L -
The voltage is regulated to P ₂ ′ −P ₂ ″ and stabilized at _{VL. For} C ₃ , the temperature control is not performed because V _BUS = V ₃ <V _L , so the current of the entire solar cell is -Voltage characteristics are:
Conventional solar cell current - will remain the same C ₃ and voltage characteristics. Therefore, V _BUS = V ₃ . The voltage range of V _BUS at this time is as follows.

[0032] V ₃ ≦ V _BUS ≦ V _L Therefore, for the case of V ₃ <V _L <V ₂ also, V _L <V
Although there is no stability (V _BUS = V _L ) as in the case of ₃ , the stability can be greatly improved as compared with the conventional stability V ₃ ≦ V _BUS ≦ V ₁ . In the case of V ₂ <V _L <V _1, a similar improvement in stability is expected.

In this way, even if the current-voltage characteristics of the solar cell are likely to fluctuate significantly as C ₁ , C ₂ , and C _{3 in} a severe space environment in which the environmental conditions are largely changed, the solar cell of the present invention can be used. The power / voltage supplied to the satellite can always be stabilized by the battery.

[0034]

As described above, according to the present invention,
In a severe space environment, the current-voltage characteristics of conventional solar cells fluctuate greatly, and a regulator and a shunt desipator were required to supply stable power / voltage to the satellite. It has stable current-voltage characteristics even in severe space environment and can be supplied directly to satellites without any need, so there is no need for regulators and shunt desiperators, and it is possible to reduce the size and weight of satellites and design heat dissipation. In addition, it is possible to obtain an effect that it is not necessary to control the entire solar cell and only small-scale temperature control of some cells is required.

The reason is that the temperature control function of some of the solar cells provided according to the present invention makes it possible to control the entire solar cell even if the current-voltage characteristics of the conventional solar cell fluctuate greatly in a severe space environment. This is because the supply power / voltage can be stabilized by stabilizing the current-voltage characteristics and keeping the operating point constant.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a current-voltage characteristic graph showing the operation of the solar cell of the present invention.

FIGS. 3A and 3B are block diagrams showing a conventional technique.

[Explanation of symbols]

C _{11 to} C _MN ... Solar cell C _{M1 to} C _MN ... Solar cell for performing temperature control CG... Control target solar cell group CNT... Temperature control circuit D _{0 to DN} ... Blocking diode BAT... Battery CHG. charging circuit L ... satellite load _{C 1, C 2, C 3} ... current conventional solar cell - voltage characteristic C _L ... load curve P _1, P ₁ satellite _{', P 1 ", P 2} , P 2' , P ₂ ″, P ₃ ,
P ₃ ′, P ₃ ″ —Operating points V ₁ , V ₂ , V ₃ , V _L on operating current-voltage characteristics of solar cell—Operating points P ₁ , P ₂ , P ₃ , P
Voltage I ₁ at _{L, I 2, I 3 ...} C 1, C 2, C current value I ₁ of the constant current region of the _{3 ', I 2', I} 3 ', I L ... P 1, P 2, P ₃ , P
Current value at _L SA… Solar cell REG… Regulator SHNT… Shunt desipator

Claims (3)

[Claims] In a solar battery device as a primary power source of an artificial satellite, a module in which solar battery cells are connected in series up to a required voltage value is connected in parallel up to a required power.
The solar cells are arbitrarily extracted one by one from each of the modules in which the solar cells are connected in series, collected at one location, and concentrated and small-scale only of the solar cells extracted according to the load power / voltage of the satellite. The constant power type by the temperature control, characterized in that the current-voltage characteristics and the power of the entire solar cell device can be stabilized even in a severe space environment where the environmental conditions change greatly by performing temperature control. Solar cells. 2. N (N is a positive integer) solar cell modules in which M (M is a positive integer) solar cells connected in series to a required voltage value, and N solar cells A control target solar cell group including N solar cells formed by connecting cell modules in parallel up to required power and arbitrarily extracting one solar cell from each of the N modules; Temperature control means for controlling the temperature of the control target solar cell group. A constant power type solar cell by temperature control. A temperature sensor for detecting a temperature of the group of solar cells to be controlled; and a heating control for keeping the temperature of the group of solar cells to be controlled constant according to a detection output of the temperature sensor. The constant-power solar cell according to claim 2, further comprising a heater that performs heating.