JPH10340125A - Constant power control type solar battery and its power control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To unnecessitate large scale constant power control of entire solar batteries and also to always feed stable power against the changes of a characteristic and load by serially connecting a constant current limiter to each of plural parallel solar battery modules and always controlling supply voltage in a constant way. SOLUTION: An entire solar battery is formed by parallelly connecting solar battery modules which serially connects M pieces of solar battery cells C1i to CMi up to i=1 to N. Here, constant current controller LMT1 to LMTN are serially connected to the solar battery modules 1 to N. The control circuit CNT detects power and voltage which are demanded by a satellite load L and controls the current values of N pieces of the constant current controllers. Controlling the current values of the controllers LMT1 to LMTN controls the other cells to the same current value, taking advantage of controlling the other cells to the same current-voltage characteristic by controlling the current- voltage characteristic of an optional cell among solar battery cells which are serially connected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a constant power control type solar cell, and in particular, such as a solar cell mounted on an artificial satellite, has a remarkable change in a power demand of a sanitary load and a change in environmental conditions and the like, and is compact. The present invention belongs to the technology of a constant power control type solar cell suitable for a case where weight reduction is required.

[0002]

2. Description of the Related Art In general, the voltage of a solar cell greatly varies depending on the power taken out, and the current-voltage characteristic varies greatly depending on environmental conditions such as temperature. Therefore, the output of the solar cell cannot be used as it is.

[0003] Therefore, for example, in a solar cell mounted on an artificial satellite, in order to suppress such a large voltage fluctuation, the voltage is stabilized by a regulator or excess power consumption using a shunt desicpator, and then the artificial satellite is operated. Stable power was supplied to each mounted device.

FIG. 3 is a conventional configuration diagram when a regulator REG is used, and FIG. 4 is a conventional configuration diagram when a shunt desipator SHNT is used. In these figures, SA is a solar cell, BAT is a battery, L is a sanitary load, CNT is a control circuit for controlling the shunt desicipator, and D1 and D2 are blocking diodes.

In FIG. 3, the regulator REG is connected in series to the sanitary load L, and the solar cell SA and the battery BAT are connected in parallel. Also,
In FIG. 4, the shunt desipator SHNT is connected in parallel to one of the plurality of solar cells connected in series, and the shunt desipator SHNT is controlled by the control circuit CNT.

[0006]

The first problem is as follows.
Conventional solar cells for mounting on sanitary devices cannot be used under severe environmental conditions such as conditions under which the sanitary load fluctuates greatly and temperature conditions. The reason is that, as described above, since the current-voltage characteristics of the solar cell fluctuate significantly, the voltage fluctuation is too large and the mounted device cannot be used as it is.

[0007] As a second problem, in order to suppress a large voltage fluctuation of the solar cell, conventionally, the voltage is stabilized by a regulator or by consuming a surplus power using a shunt desicpator, and then the load and the load are reduced. However, all of these methods have drawbacks in that heat is concentrated in one place and increase in weight and volume, which is an obstacle to reducing the size and weight of satellites. It has become. The reason is that the regulator and the shunt dessipator in the conventional method need to process a large amount of electric power of the entire solar cell, so that the size and the heat generation, the weight, and the volume are all large.

Therefore, an object of the present invention is to control the current-voltage characteristics of the entire solar cell according to a change in load power demand and a change in environmental conditions only by adding a simple circuit. Enables stable supply of voltage and power according to required power without requiring large-scale constant power control of the entire battery, and reduces the size and weight by eliminating the regulator and shunt desipator that were required in the past. It is to provide a technology that makes it possible.

[0009]

In order to solve the above-mentioned problems, a constant power control type solar cell according to the present invention comprises a plurality of solar cells connected in series and in parallel, and N solar cells composed of those solar cells. The configuration includes a parallel solar cell module wool, N constant current limiters connected in series for each solar cell module, and control means for controlling each constant current limiter.

Here, the control means may be configured to include a function of controlling the current value of the N constant current limiters according to the required power and voltage of the load.

Further, the solar battery may be mounted on an artificial satellite, and the load may be various devices mounted on the artificial satellite.

On the other hand, in the control method of the present invention, a plurality of solar cells are connected in series and in parallel to form a solar cell having a required power, and the current value of the solar cell is controlled to meet a load demand. A power control method for a constant power control type solar cell that supplies corresponding stable power and voltage, wherein a plurality of solar cells are divided into N parallel solar cell modules, and current value control is performed for each module. By doing so, a method of controlling the current-voltage characteristics of the entire solar cell was adopted.

In this case, the current value control for each solar cell module can be performed using a constant current limiter connected in series for each solar cell module.

[0014] The solar battery may be mounted on an artificial satellite, and the load may be various devices mounted on the artificial satellite.

In general, when an arbitrary number of solar cells are connected in series, the current value of all the solar cells connected in series is controlled by controlling the current value of any one of the solar cells. Voltage characteristics can be controlled.

Utilizing this feature, a total of N constant current limiters connected in series to each of the N parallel divided solar cell modules can be used in accordance with the power and voltage required by sanitation. The current value of the N constant current limiters is controlled by the feedback signal, and the current-voltage characteristics of the entire solar cell are controlled by the feedback signal. Power and voltage can be supplied. By this means, large-scale constant power control of the entire solar cell becomes unnecessary, and
Since it is sufficient to simply add N constant current limiters, a regulator and a shunt desipator, which have been conventionally required, are not required, and the hygiene can be reduced in size and weight.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below with reference to FIGS. FIG.
Is a block diagram of the constant power control type solar cell according to the present embodiment, and FIG. 2 is a graph showing the operation (current-voltage characteristics).

In FIG. 1, C11, C21,..., CM1, C
12, C22, CM2,..., C1N, C2N, and CMN are solar cells. A solar cell module (i) in which M solar cells of C1i, C2i,..., CMi are connected in series from i = 1
It is assumed that the entire solar cell is configured by connecting up to N in parallel.

LMT1, LMT2,..., LMTN are constant current limiters, which are connected in series to the solar cell modules 1 to N, respectively. CNT is a control circuit that has a function of detecting the power and voltage required by the satellite load L and controlling the current values of the N constant current limiters. As the control circuit CNT, a conventional control circuit for controlling the shunt dessipator according to the required power and voltage of the sanitary load can be used as it is.

D1 to DN are blocking diodes provided to restrict the flow of reverse current to each solar cell module.

Next, the operation will be described with reference to FIG.

In FIG. 1, C0 and C1 indicate current-voltage characteristics, and L1 and L2 indicate satellite load curves. P
0, P0 ', P0 ", P1, P1', PL, PL ', PL"
Is the operating point on the current-voltage characteristic of the solar cell or the satellite load curve. VL is the voltage supplied to the satellite load, I
L is the satellite load current.

In FIG. 2, it is assumed that the current-voltage characteristic of the solar cell is C0. It is also assumed that the satellite load curve is in the state of L1. At this time, if the output of the solar cell is directly supplied to the satellite load L, the operating point becomes P0 and the supply voltage becomes V0. However, it is assumed that the required voltage of the satellite load L is VL.

Generally, when an arbitrary number of solar cells are connected in series, if the current-voltage characteristics of any of the cells are controlled, the other cells are also controlled to have the same current-voltage characteristics. . Therefore, the constant current limiter L is applied to an arbitrary number of series-connected solar cell modules (1) to (N).
By connecting MT1 to LMTN and controlling the current values of their constant current limiters, the other cells are also controlled to the same current value.

Using this operating principle, the current value is controlled to IL using N constant current limiters, and the constant current limiters are set so that the supply voltage at this time becomes VL. And At this time, the operating point on C0 is P0 ', and is set to PL on the satellite load curve L1 after passing through the constant current limiter.

Next, it is assumed that the current-voltage characteristic of the solar cell has changed to C1. At this time, the set value of the constant current controller (I
(L, V0-VL), the supply voltage is about to change from VL to VL '. At this time, the supply voltage VL is detected by the control circuit CNT in FIG. 1 and each constant current limiter current value is controlled. By this means, even if the current-voltage characteristic of the solar cell changes to C1, the supply voltage does not become VL 'but is controlled to VL.

Next, it is assumed that the satellite load curve has changed to L2. At this time, if the set value of the constant current limiter is
The operating point moves to PL ", and the supply voltage tries to change to VL". However, the supply voltage is controlled to VL by controlling the current value of each constant current limiter by the control circuit CNT. At this time, the current value is controlled to IL ", the operating point on the satellite load curve is set to PLL, and the operating point on the current-voltage characteristic C0 of the solar cell is set to P0".

According to such an operation principle, the control circuit CN
By controlling the current values of the N constant current limiters using T and controlling the supply voltage to a constant value, power and voltage that are always stable against fluctuations in solar cell characteristics and fluctuations in the satellite load L can be obtained. Can be supplied.

[0029]

As described above, according to the present invention,
A constant current limiter is connected in series to each of the N parallel solar cell modules constituting the solar cell, and the supply voltage is always kept constant by simple control of only a total of N simple circuits. Therefore, it is possible to always supply stable power and voltage to the satellite load with respect to the fluctuation of the solar cell characteristic and the change of the satellite load without requiring large-scale constant power control of the entire solar cell.

In addition, since only N simple constant current limiters are required, the size and weight of the satellite are smaller than those of regulators and shunt desipators that perform high power processing, which is conventionally required. Can be.

[Brief description of the drawings]

FIG. 1 is a block diagram of a constant power control type solar cell according to an embodiment of the present invention.

FIG. 2 is a graph showing an operation of the constant power control type solar cell according to the embodiment of the present invention.

FIG. 3 is a block diagram showing a conventional example.

FIG. 4 is a block diagram showing a conventional example.

[Explanation of symbols]

C11, C21, CM1, C12, C22, CM2, C1N, C2N, C
MN solar cell D1 to DN blocking diode LMT1 to LMTN low current limiter CNT control circuit BAT battery L satellite load C0, C1 current-voltage characteristic L1, L2 satellite load curve P0, P0'P0 "operating point P1, P1 'operation Point PL, PL ", PLL Operating point SA Solar cell V0, V0 ', V1, V1', VL, VL ', VL" Voltage REG Regulator SHNT Shunt desipeater

Claims (6)

[Claims] 1. A plurality of solar cells connected in series and in parallel, N parallel solar cell modules composed of those solar cells, and N constant currents connected in series for each solar cell module A constant power control type solar cell including a limiter and control means for controlling each constant current limiter. 2. The constant power control type according to claim 1, wherein said control means has a function of controlling current values of N constant current limiters according to a required power and a voltage of a load. Solar cells. 3. The constant power control type solar cell according to claim 1, wherein the solar cell is mounted on an artificial satellite, and the load is a device mounted on an artificial satellite. 4. A plurality of solar cells are connected in series and in parallel to form a solar cell of required power, and by controlling the current value of the solar cell, stable power and voltage corresponding to a load requirement are provided. A power control method for a constant power control type solar cell that supplies a plurality of solar cells by dividing the plurality of solar cells into N parallel solar cell modules and performing current value control for each module. A power control method for a constant power type solar cell, comprising: controlling an entire current-voltage characteristic. 5. The constant power control type solar cell according to claim 4, wherein the current value control for each solar cell module is performed using a constant current limiter connected in series for each solar cell module. Power control method. 6. The power control method for a constant power control type solar cell according to claim 4, wherein the solar cell is for mounting on an artificial satellite, and the load is various types of equipment mounted on the artificial satellite.