JPH07231578A - Solar battery power supply system - Google Patents

Abstract

PURPOSE:To constitute a solar battery power supply system which provides an interface with a solar array bus lockup system easily even when a plurality of charging/discharging systems are present. CONSTITUTION:A charging/discharging current operating unit 14a is inserted between charging/discharging current monitors 11a-11n and a solar array bus lockup decision unit 13 so that the output is limited arbitrarily to only one based on the charging/discharging current monitor signals from a plurality of systems thus providing an interface easily. Since one monitored value of charging/discharging current can be outputted even when a plurality of monitor currents are present for the parallel constitution of the system associated with a large scale satellite, an interface to a solar array bus lockup decision unit can be provided easily.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention supplies electric power to a load from a solar cell by a shunt device during sunshine,
In a solar battery power supply system such as a satellite that supplies power to the load by discharging the storage battery during shade, the voltage of the solar battery power supply system during sunshine is fixed to the storage battery voltage, and the load can be supplied only by the generated power of the solar battery. Regardless of this, a charging / discharging current calculation that can calculate and output n charging / discharging current monitor values that are input signals of the solar array bus lockup determination device that determines that the battery has been discharged for a long time. It relates to the device.

[0002]

2. Description of the Related Art FIG. 5 is a block diagram of a conventional solar battery power supply system, in which 1 is a solar battery, 2 is a storage battery, 3 is an anode connected to the output end of the solar battery 1, and its cathode is a power supply bus. The constituting blocking diodes 4 are connected in parallel with the solar cell 1 between the anode of the blocking diode 3 and a return line (hereinafter, simply referred to as RTN), and a shunt that consumes the surplus electric power generated in the solar cell 1. A device 5 is a discharge diode whose cathode is connected to the power supply bus, and 6 is a parallel connection to the discharge diode 5 on the power supply bus.
A charger for charging the power source, 7 is a capacitor bank connected between the power bus and RTN, 8 is a load connected between the power bus RTN, and 9 is a current value flowing from the blocking diode 3 to the power bus. The solar array current monitor 10 detects the current, converts it into a telemetry signal ISA-TLM and sends it out, and 10 detects the current value flowing into the load 8 from the above power supply bus and converts it into the telemetry signal IMB-TLM and sends it out. A monitor, 11 is connected between the discharge diode 5 and the storage battery 2, detects a charge / discharge current value of the storage battery 2, converts it into a telemetry signal ID / C-TLM, and sends it out. A bus voltage monitor that detects the voltage of the capacitor bank 7, converts it to a telemetry signal VMB-TLM and sends it out, and 13 is the solar array current monitor 9 and the load current monitor. A solar array bus lockup determination device that calculates output signals of the battery 10, the charge / discharge current monitor 11, and the bus voltage monitor 12, detects the solar array bus lockup state, and sends a power reduction signal to the load. is there. Hereinafter, the operation of the conventional power supply device will be described in detail.

During sunlight, the electric power generated by the solar cell 1 is supplied to the load 8 via the blocking diode 3. Part of the electric power generated by the solar cell 1 that exceeds the power consumption of the load 8 is the charger 6
Is supplied as charging power to the storage battery 2 via the battery and is consumed by the shunt device 4 when there is a surplus.
At this time, the voltage of the capacitor bank 7 (hereinafter referred to as bus voltage) is stabilized to a value of VSHNT. In general,
The bus voltage VSHNT is always selected higher than the voltage VBAT of the storage battery 2.

FIG. 6 shows the relationship between the power generated by the solar cell 1 and the load power consumed by the load 8. The power generated by the solar cell 1 is represented by the IS-VS curve in FIG. On the other hand, the load 8 is generally treated as a constant power load because a DC / DC converter is built in the inside and the bus voltage is converted into an appropriate constant voltage to consume power. Therefore, the relationship between the bus voltage and the load current is a curve represented by P-P 'in FIG. As described above, the shunt device 4 controls the solar cell 1 to stabilize the bus voltage at VSHNT.
Since the surplus power generated in is consumed, the power operating point is
Is the intersection A of M-M 'and P-P'.

On the other hand, since the power generated by the solar cell 1 cannot be obtained in the shade, the storage battery 2 is discharged to supply the load 8 through the discharge diode 5. At this time, the bus voltage is the voltage VBAT depending on the discharge voltage of the storage battery 2.
Becomes

In order to monitor the operating state of the power supply system, the solar array current monitor 9, the load current monitor 10, the charge / discharge current monitor 11 and the bus voltage monitor 12 detect the state of each part and convert it into a telemetry signal to convert it to ground. Send to the station.

FIG. 7 shows the transition of the power operating point when the load power fluctuates during sunshine. In FIG. 7, the IS-VS curve is the generated current-voltage characteristic of the solar cell 1, VBAT is the bus voltage when the storage battery 2 is discharging, and VSHNT is the surplus power control of the solar cell 1 by the shunt device 4. And is the stabilized bus voltage value.

Now, consider a case where the power consumption of the load 8 fluctuates when the power consumption of the load 8 is P1 and the operating point is the point A. When the power consumption of the load 8 fluctuates within a range not exceeding VSHNT × IS, the power operating point is the straight line M- in FIG.
It is on M '. However, the power consumption of load 8 is VSHNT × I
When P1 is increased to P2 by exceeding S, the generated power of the solar cell 1 is exceeded, so that the operation of compensating for the insufficient power by discharging the storage battery 2, and the power operating point moves from A to M to B.

Once the power operating point moves to point B, even if the power consumption of the load 8 returns to P1 immediately thereafter,
The power operating point cannot be returned to the point A, and the bus voltage is fixed to the discharge voltage of the storage battery 2 even though the solar cell 1 has enough generated power to cover all the load power simply by moving to the point C. A solar array bus lockup phenomenon occurs in which discharge from the storage battery 2 cannot be avoided.

Therefore, the solar array bus lockup determination device detects the above-mentioned solar array bus lockup state by using each of the load current monitor 10, charge / discharge current monitor 11, and bus voltage monitor 12 telemetry monitors. This is automatically avoided by sending a control signal to the load 8 to temporarily reduce the load power to P3 or less in FIG. In other words, the power operating point changes from C → D → E,
The bus voltage can be returned to the regulated voltage VSHNT during sunshine. It is clear that if the load power is reset to P1 again, it will return to the power operating point A in the steady state.

A method of determining the solar array bus lockup in the solar array bus lockup determination device 13 will be described below. First, the charge / discharge current monitor 11
Confirm that the storage battery 2 is in the discharged state by the telemetry ID / C-TLM of. Here, the value obtained by engineering conversion of the telemetry ID / C-TLM of the charge / discharge current monitor 11 is ID / C, the value obtained by engineering conversion of the telemetry Isa-TLM of the solar array current monitor 9 is ISA, and the telemetry IMB of the load current monitor 10 is MB-. When the value obtained by engineering conversion of TLM is IMB, the value obtained by engineering conversion of telemetry VMB-TLM of the bus voltage monitor 12 is VMB, and the stabilized bus voltage value by the shunt device 4 at the time of sunshine is VSHNT, the solar cell 1 is effectively generated. Calculate the power and load power using the above values. When the following expression is established, a load power reduction signal is sent to the load 8 and the solar array bus lockup state is automatically avoided. VSHNT × ISA> VMB × IMB

In the example shown in FIG. 5, the load current monitor I
It can also be determined by replacing MB with the following formula. IMB = ISA + ID / C

[0013]

In recent years, the parallel use of storage batteries has become mainstream with the increase in the power of orbiting satellites, and a plurality of charge / discharge systems, which were conventionally composed of one system, are constructed. The solar power supply system has become indispensable. However, since the solar array bus lockup determination device mounted on the above-described solar battery power supply system does not include the charging / discharging current monitor signal input for one system, n charging / discharging current monitor signals are input. In order to process the above, a new development of a solar array bus lockup determination device is required, and there is a problem that it is difficult to adopt it from the viewpoint of development cost and development schedule. Further, since the number of systems n is different for each satellite, it is necessary to construct a flexible power supply system.

The present invention has been made to solve the above problems, and obtains a structure of a solar cell power supply system that can easily interface with a solar array bus lockup determination device even when there are a plurality of charge / discharge systems. With the goal.

[0015]

In the solar cell power supply system according to the present invention, a charge / discharge current calculation device is provided between the charge / discharge current monitor and the solar array bus lockup determination device so that the interface can be facilitated. It is composed.

Further, the present invention is provided with a charging / discharging current calculating device for calculating n charging / discharging current monitor signals and detecting the maximum value among the n charging / discharging current monitor signals.

The present invention is provided with a charging / discharging current calculating device for calculating n charging / discharging current monitor signals and detecting the minimum value of n.

Further, the present invention is provided with a charging / discharging current calculating device for calculating an average value of n monitoring signals from n charging / discharging current monitor signals.

The present invention is provided with a selection circuit for selecting any one of the n charge / discharge current monitor signals in accordance with the ground station command command.

[0020]

In the present invention, when there are a plurality of charging / discharging systems, n charging / discharging current monitor signals are calculated or any one of them is calculated.
By selecting a signal and outputting it to the solar array bus lockup determination device, the solar array bus lockup state is determined as in the conventional case.

Further, according to the present invention, when there are a plurality of charging / discharging systems, n charging / discharging current monitor signals are calculated,
By detecting the maximum value out of n and outputting it to the solar array bus lockup determination device, the solar array bus lockup state is determined as in the conventional case.

According to the present invention, when there are a plurality of charging / discharging systems, n charging / discharging current monitor signals are calculated, the minimum value of n is detected, and the result is output to the solar array bus lockup determination device. Thus, the solar array bus lockup state is determined as in the conventional case.

Further, according to the present invention, when there are a plurality of charge / discharge systems, n charge / discharge current monitor signals are calculated,
By calculating the n average values and outputting them to the solar array bus lockup determination device, the solar array bus lockup state is determined as in the conventional case.

According to the present invention, when there are a plurality of charging / discharging systems, any one of the n charging / discharging current monitor signals is selected in accordance with a ground station command command and is output to the solar array bus lockup determination device. Thus, the solar array bus lockup state is determined as in the conventional case.

[0025]

【Example】

Example 1. First Embodiment FIG. 1 is a diagram showing a first embodiment of the present invention.
Reference numeral 13 is exactly the same as the conventional solar cell power supply system.
14a is a charge / discharge current calculation device, 15 is a maximum value detection circuit,
16a is a level conversion circuit. The charge / discharge current calculation device will be described below.

In a solar cell power supply system composed of at least two charge / discharge current monitors, the maximum value detection circuit 15 outputs n charge / discharge current telemetry values from the charge / discharge current monitor 11a to the charge / discharge current monitor 11n. It receives it as an input signal, sequentially compares each value, and detects the maximum value among them. Only one charge / discharge current monitor that outputs the maximum value is selected, sent to the level conversion circuit 16a, level-converted, and then output to the solar array bus lockup determination device 13. Therefore, by outputting the maximum ID / C-SIG from the charging / discharging current monitor values of n systems,
A conventional solar array bus lockup determination device for a solar cell power supply system can be used as it is, and determination of the solar array bus lockup state is possible.

Example 2. FIG. 2 is a diagram showing a second embodiment of the present invention, in which 1 to 13 are completely the same as those of the conventional solar cell power supply system. Reference numeral 14b is a charge / discharge current calculation device, 16b is a level conversion circuit, and 17 is a minimum value detection circuit. The charge / discharge current calculation device will be described below.

In the solar cell power supply system including at least two charge / discharge current monitors, the minimum value detection circuit 17 detects n charge / discharge current telemetry values from the charge / discharge current monitor 11a to the charge / discharge current monitor 11n. It receives it as an input signal, sequentially compares each value, and detects the minimum value among them. Only one charge / discharge current monitor that outputs the minimum value is selected, sent to the level conversion circuit 16b, level-converted, and then output to the solar array bus lockup determination device 13. Therefore, by outputting the smallest ID / C-SIG from the charge / discharge current monitor values of n systems,
A conventional solar array bus lockup determination device for a solar cell power supply system can be used as it is, and determination of the solar array bus lockup state is possible.

Example 3. FIG. 3 shows an embodiment to which the first invention and the fourth invention of the present invention are applied, in which 1 to 13 are completely the same as those of the conventional solar cell power supply system. Reference numeral 14c is a charge / discharge current calculation device, 16c is a level conversion circuit, 18 is an addition circuit, and 19 is a division circuit. The charge / discharge current calculation device will be described below.

In the solar cell power supply system including at least two charge / discharge current monitors, the adder circuit 1
Reference numeral 8 receives from the charge / discharge current monitor 111a n charge / discharge current telemetry values of the charge / discharge current monitor n11n as input signals and adds them all together. The value is sent to the division circuit 19 and the division circuit 19 calculates the number of charging / discharging systems.
Then, the value is level-converted by the level conversion circuit 16c and then output to the solar array bus lockup determination device 13. Therefore, it is the average of the charge / discharge current monitor values of n systems. By outputting ID / C-SIG, the conventional solar array bus lockup determination device for the solar cell power supply system can be used as it is, and the determination of the solar array bus lockup state can be performed.

Example 4. FIG. 4 shows an embodiment to which the first invention and the fifth invention of the present invention are applied, in which 1 to 13 are completely the same as those of the conventional solar cell power supply system. Reference numeral 14d is a charge / discharge current calculation device, 16d is a level conversion circuit, and 20 is an input signal selection circuit. The charge / discharge current calculation device will be described below.

In the solar cell power supply system including at least two charge / discharge current monitors, the input signal selection circuit 20 includes n charge / discharge current monitors 1 11a to n 11n. It receives the telemetry value as an input signal and the optimum 1
Select one charge / discharge current monitor value. The value is level-converted by the level conversion circuit 16d and then output to the solar array bus lockup determination device 13. Therefore, the solar array bus lockup determination device of the conventional solar cell power supply system can be used as it is by outputting as the ID / C-SIG the one that has been determined to be the optimum from among the n system charge / discharge current monitor values. Moreover, it becomes possible to judge the solar array bus lockup state.

[0033]

Since the present invention is configured as described above, even if there are a plurality of charging / discharging current monitor signals in the parallel configuration of the charging / discharging system accompanying the increase in size of the artificial satellite, an arbitrary 1 Since one charge / discharge current monitor value can be output, there is an advantage that the conventional solar array bus lockup determination device can be used as it is, and the solar array bus lockup can be easily released automatically.

Further, the present invention has an advantage that the detection of the solar array bus lockup state can be made slower by selecting the maximum value as any one charge / discharge current monitor value, and the load operation can be given the highest priority.

Further, the present invention has an advantage that the detection of the solar array bus lockup state is sharpened by selecting the minimum value as any one charge / discharge current monitor value, and the satellite bus protection is prioritized.

According to the present invention, the detection of the solar array bus lockup state is set to the nominal state by selecting the average value as any one charge / discharge current monitor value, and the satellite load is operated to the maximum while protecting the satellite bus. There is an advantage that you can.

Further, according to the present invention, one of the charging / discharging current signals can be selected by the ground station command, so that the satellite operation with a high degree of freedom as described above can be performed in response to the load request.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a solar cell power supply system showing a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a solar cell power supply system showing Embodiment 2 of the present invention.

FIG. 3 is a configuration diagram of a solar cell power supply system showing Embodiment 3 of the present invention.

FIG. 4 is a configuration diagram of a solar cell power supply system showing Embodiment 4 of the present invention.

FIG. 5 is a configuration diagram of a conventional solar cell power supply system.

FIG. 6 is a diagram showing a relationship between load power and generated power of a conventional solar cell.

FIG. 7 is a diagram showing transition of a power operating point in occurrence and avoidance of a solar array bus lockup.

[Explanation of symbols]

 1 Solar Battery 2 Storage Battery 3 Blocking Diode 4 Shunt Device 5 Discharge Diode 6 Charger 7 Capacitor Bank 8 Load 9 Solar Array Current Monitor 10 Load Current Monitor 11 Charge / Discharge Current Monitor 12 Bus Voltage Monitor 13 Solar Array Bus Lockup Judgment Device 14 Charge Discharge current calculation device 15 Maximum value detection circuit 16 Level conversion circuit 17 Minimum value detection circuit 18 Addition circuit 19 Division circuit 20 Input signal selection circuit

Claims (5)

[Claims] 1. A solar cell, and a shunt device connected in parallel between an output terminal and a return line of the solar cell,
Between the first diode whose anode is connected to the output terminal of the solar cell, the solar array current monitor whose output end is connected to the cathode of this diode to form a power supply bus, and between the power supply bus and the return line N chargers connected in series, charge / discharge current monitor, and storage battery,
N discharge diodes whose cathodes are connected to the power supply bus and are connected in parallel with the charger; bus voltage monitors and bus capacitors connected in parallel between the power supply bus and the return line; and the power supply bus. A solar cell using a load current monitor connected in series between return lines, an output signal of the bus voltage monitor, an output signal of the load current monitor, an output signal of the charge / discharge current monitor, and an output signal of the solar array current monitor. In a solar cell power supply system including a solar array bus lockup determination device that detects a solar array bus lockup state of the power supply system and sends a control signal for reducing the load to the load, the above n charging / discharging currents Using the monitor value as the input source, one of n values is selected or the result of calculating n values is used as the solar array bus lockup determination device. Solar power supply system provided with the charging and discharging current calculation device which can output as the input signal. 2. The solar cell power supply system according to claim 1, wherein the output signal of the charge / discharge current calculation device is the maximum value of the n charge / discharge current monitors. 3. The solar cell power supply system according to claim 1, wherein an output signal of the charge / discharge current calculation device is a minimum value of the n charge / discharge current monitors. 4. The solar cell power supply system according to claim 1, wherein the output signal of the charge / discharge current calculation device is an average value of the n charge / discharge current monitor values. 5. The solar battery power supply system according to claim 1, wherein an arbitrary output signal of the charging / discharging current calculation device can be selected by a ground station command to select any one charging / discharging current monitor value.