JPH0720351B2 - Solar array bath lockup determination device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention, for example, supplies power to a load by stabilizing the voltage from a solar cell by a shunt device during sunshine, and supplies power to the load from a storage battery during shade. In the solar power supply system for artificial hygiene to be supplied, the voltage of the solar power supply system during sunshine is fixed to the storage battery voltage and the load can be supplied only by the power generated by the solar battery, but the storage battery is also discharged for a long time. The present invention relates to a solar array bus lockup determination device that determines that a current state has been reached (hereinafter referred to as solar array bus lockup) and temporarily reduces the load to restore the voltage stabilized state by a shunt device. .

[Conventional technology]

Fig. 2 is a block diagram of a conventional solar cell power supply system.
Is a solar cell, (2) is a storage battery, (3) and (4) are diodes, and the anode of the diode (3) is the solar cell (1).
The anode of the diode (4) is connected in series with the output of the storage battery (2), and the cathodes of the diode (3) and the diode (4) are connected to form a power supply bus. (5) is a shunt device that is connected in parallel with the solar cell (1) between the anode of the diode (3) and the RTN, and consumes excess power generated by the solar cell (1), and (6) is the power supply A charger (7) connected in series between the bus and the storage battery (2) for charging the storage battery (2) during sunshine is a power supply bus and RTN.
The capacitor bank (8) connected in between is a load, and the load amount is set by a command from the ground station. (9) is a solar array current monitor that detects the current level flowing into the power supply bus from the diode (3), converts it to a telemetry signal, and sends it out, and (10) is the load (8) from the power supply bus.
A load current monitor that detects the current level flowing out to the telemetry signal and sends it out by converting it into a telemetry signal. (11) detects the charging / discharging flow level of the storage battery (2) and converts it into a telemetry signal and sends it out. A current monitor (12) is a bus voltage monitor that detects the voltage level of the capacitor bank (7), converts it into a telemetry signal, and outputs it.

The operation of the conventional solar cell power supply system will be described in detail below.

During sunshine, part of the electric power generated by the solar cell (1) is converted by the charger (6) through the diode (3) and becomes the charging power of the storage battery (2), and the rest is the load ( It becomes the power consumption of 8). At this time, the shunt device (5) consumes the surplus power generated in the solar cell (1) and controls the power passing through the diode (3) to control the voltage of the capacitor bank (7) (hereinafter referred to as the bus voltage). That) is stabilized to V _SHNT . V _SHNT is always selected higher than the voltage V _BAT of the storage battery (2).

FIG. 3 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. The load (8) generally has a built-in DC / DC converter and converts the bus voltage into an appropriate constant voltage for power consumption, so it looks like a constant power load.

Therefore, the relationship between the load voltage and the load current becomes a constant power curve represented by P-P 'in FIG.

As described above, the shunt device (5) consumes the surplus power generated in the solar cell (1) so as to stabilize it at the bus voltage V _SHNT , so the power operating point is the straight line MM ′ in FIG. 3 and the constant power line. It is the intersection A of P-P '.

Since the generation of electric power in the solar cell (1) is stopped during the shade, the storage battery (2) is discharged to supply power to the load (8) through the diode (4).

In order to monitor the operating state of the power supply system, the solar array current monitor (9), load current monitor (10), charge / discharge current monitor (11) and bus voltage monitor (12) detect the current level or voltage level of each part and perform telemetry. It is converted to a signal and sent to the ground station.

[Problems to be Solved by the Invention]

Now, FIG. 4 shows the transition of the electric power operating point when a load change occurs during sunshine. In Figure 4, the Is-Vs curve is the current-voltage characteristic of the solar cell (1), and V _BAT is the storage battery (2).
The output voltage of V _SHNT , V _SHNT, is the regulated voltage by the shunt device (5).

Now, consider a case where the power consumption of the load (8) fluctuates when the power consumption of the load (8) is P ₁ and the operating point is the point A. When the power consumption of the load (8) fluctuates within a range not _exceeding V _SHNT × I _S , the power operating point is the straight line MM ′ in FIG.
It is above. However, if the power consumption of the load (8) exceeds V _SHNT × I _S and increases from P ₁ to P ₂ , the amount of power generated by the solar cell (1) will be exceeded and the power will be supplemented by discharging the storage battery (2). The power operating point moves from A to B.

Once the operating point moves to point B, immediately after that load (8)
Even if the power consumption of P is reduced to P ₁ , the operating point does not recover to A point but moves to C point, and the solar cell (1) has enough power generation capacity to supply all the load power.
The phenomenon that the bus voltage is fixed to the voltage of the storage battery (2) and discharge continues from the storage battery (2) (solar array bus lockup) occurs. To release the solar array bus lockup, load by command from the ground (8)
Power consumption is temporarily reduced to P ₃ or less and the operating point is changed from C to D
→ E → A must be transitioned.

If the solar array bus lockup is left unattended, the storage battery (2) will always be in a discharged state, and the balance of electric power balance of the storage battery during the sunshine and the shade will be lost.

In order to determine whether or not a solar array bus lockup has occurred, conventionally, after confirming that the storage battery (2) is discharging by telemetry of the charge / discharge current monitor (11),
Solar array current monitor (9) telemetry I _SARY and load current monitor (10 telemetry I _L and bus voltage monitor (1
Using the telemetry V _{BUS of} 2) and the stabilizing voltage V _SHNT by the shunt device (5), calculate _whether V _SHNT × I _SARY > V _BUS × I _L (1) is established by a ground computer, and (1) It was determined that the solar array bass lockup had occurred when the formula was satisfied.

However, this method is premised on that a ground station can always communicate with a satellite like a geostationary satellite, and a low-altitude orbit satellite such as an orbiting satellite cannot communicate with the satellite for a longer period of time than the ground station. If a solar array lockup occurs in the system, how to quickly release the solar array lockup was a challenge.

SUMMARY OF THE INVENTION An object of the present invention is to provide a solar array bus lockup determination device that automatically determines the occurrence of a solar array bus lockup, temporarily reduces the load, and releases the solar array bus lockup.

[Means for Solving the Problems]

The solar array bus lockup determination device according to the present invention includes two multipliers that calculate the power and load power that can be effectively extracted from the solar cell from the output of one reference power source and the telemetry signal, and the two multipliers. It is composed of one comparator that sends a load power reduction signal to the load when it is determined that the state of the solar cell power supply system is the solar array bus lockup by comparing the outputs.

[Action]

According to the present invention, when the load current temporarily exceeds the current generated by the solar cell and the bus voltage is fixed to the voltage of the storage battery, the effective generated power of the solar cell and the load power are calculated to determine the effective power of the solar cell. If it determines that the generated power is greater than the load power, it sends a load power reduction signal to the load. As a result, the discharge from the storage battery is stopped, and power is supplied to the load only by the output power of the solar cell while the voltage is stabilized by the shunt device. That is, the determination and cancellation of the solar array bus lockup are performed.

〔Example〕

FIG. 1 is a configuration diagram showing an embodiment of the present invention incorporated in a solar cell power source system, and (1) to (12) are exactly the same as the conventional components. (13) is a solar array bus lockup determination device, (14) is a reference power source, (15) (16)
Is a multiplier and (17) is a comparator.

The solar array bus lockup determination device (13) including the reference power source (14), the multipliers (15) (16) and the comparator (17) will be described in detail below.

The multiplier (15) is connected to the telemetry output terminal of the solar array current monitor (9), the telemetry output terminal of the charge / discharge current monitor (11) and the output terminal of the reference power supply (14), and the solar array current monitor (9) is connected. telemetry output by multiplying the output V _REF of I _STLM and the reference power supply (14), further charging and discharging people flow monitor (12) multiplied by the charge and discharge condition coefficient outputting a signal P _s to the comparator (17) of the To do. Multipliers (16)
Is connected to the telemetry output terminal of the load current monitor (10) and the telemetry output terminal of the bus voltage monitor (12). The telemetry output I _{LTLM of the} load current monitor (10) and the telemetry output V of the bus voltage monitor (12) are connected. Multiplies _BUSTLM and outputs the signal P _L to the comparator (17).

Input signal (I _STLM , to each of the above multipliers (15) (16),
V _REF , I _LTLM , and V _BUSTLM are given by equations (2) to (5).

I _STLM = _k1 I _s (2) V _REF = _k2 V _REF (3) I _LTLM = _k1 I _L (4) V _BUSTLM = _k2 V _BUS (5) (2) (4) In formula (5), k ₁ , k ₂ is a conversion constant coefficient when converting an actual current level or voltage level into a telemetry signal. In addition, the output of the reference power source (14) is the regulated voltage V _SHNT during sunshine by the shutter device (5).
Is set so that the relationship expressed by the equation (3) holds.

At this time, the outputs P _S and P of each of the multipliers (15) and (16) are
_L is expressed by equations (6) and (7) using equations (2) to (5).

_{P S} = k1k2 V _SHNT I _SARY factor M in _{· M (6) P L =} k1k2 V BUS I L (7) (6) formula, the charging and discharging people flow monitor (1
In the charging / discharging state coefficient of 2), M = 0 when the storage battery is in the charging state, and M = 1 when the storage battery is in the discharging state.

The comparator (17) is connected to the output terminals of the multipliers (15) and (16) and compares the output signals P _S and P _L of the multipliers (15) and (16) with P _S > P _L (8) Outputs a load reduction signal to the load (8) when the above condition occurs.

Now, if a solar array bus lockup occurs, the charge / discharge state coefficient M in the equation (6) is M = 1 because the storage battery (2) is discharged.

At this time, the equation (8) is established and the load reducing signal is sent from the comparator (17) to the load (8) to reduce the load amount.

When the load amount is reduced and the solar array bus lockup is released, the storage battery (2) changes to the charged state, so the charge / discharge state coefficient M in the equation (6) changes to M = 0. Due to the change in the value of M, the expression (8) is not satisfied and the output of the load reduction signal from the comparator (17) is stopped.

〔The invention's effect〕

As described above, the present invention is a solar array bus lockup configured to calculate the effective generated power and load power of a solar cell and send a load power reduction signal to the load when the effective generated power is larger than the load power. By connecting the judgment device to the PV power supply system, there is an advantage that the occurrence of the solar array bus lockup can be automatically judged and canceled without always losing the load function and without the assistance of the ground station. .

[Brief description of drawings]

FIG. 1 is a block diagram of a solar array bath lockup determination device connected to a solar cell power source system according to an embodiment of the present invention, FIG. 2 is a block diagram of a conventional solar cell power source system, and FIG. FIG. 4 is a diagram showing the relationship between the generated power of the battery and the load power, and FIG. 4 is a diagram showing the transition of the power operating point when the solar array bus lockup is generated and released. In the figure, (1) is a solar cell, (2) is a storage battery,
(3) (4) is a diode, (5) is a shunt device,
(6) is a charger, (7) is a capacitor bank, (8) is a load, (9) is a solar array current monitor, (10) is a load current monitor, (11) is a charge / discharge current monitor, and (12) is a bus. Voltage monitor, (13) solar array bus lockup determination device, (14) reference power supply, (15) and (16) multipliers,
(17) is a comparator. The same reference numerals in the drawings indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A solar cell, an output terminal of the solar cell, and an RTN.
A shunt device connected in parallel between them, and a first diode whose anode is connected to the output terminal of the solar cell,
A solar array current monitor connected in series to the cathode of this diode to form a power supply bus at the output end, a charger, a charge / discharge current monitor, and a storage battery connected in series between the power supply bus and RTN, and a cathode connected to the power supply bus. Second diode connected to the charge / discharge current monitor in parallel with the charger, bus voltage monitor and capacitor bank connected in parallel between the power bus and RTN, and load connected in series between the power bus and RTN In a solar cell power supply system including a current monitor and a load, a first calculator for calculating the effective generated power of the solar cell based on the telemetry output of the solar array current monitor and the output of the charge / discharge current monitor, and the bus. A second calculator for calculating load power consumed by the load based on the telemetry output of the voltage monitor and the telemetry output of the load current monitor; The input terminal is connected to the output terminal of the first computer and the second output terminal, the output terminal is connected to the command input terminal of the load, and the effective power generation of the solar cell is larger than the load power. A solar array bus lockup determination device comprising a comparator for outputting a load power reduction signal to the load.