JPS58175929A - Method of controlling power feeding system using solar battery - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to the operational control of a power supply system in which a solar cell and a storage battery are arranged in parallel as energy storage means, and from which power is supplied to another AC power supply system via a power converter. be.

FIG. 1 is a configuration diagram showing an example of a conventional power supply system of this type. In the figure, 11+ is a solar cell, (21 is a storage battery, (31 is an inverter, (4) is another AC power supply system, (5) is the current or power control circuit of the inverter,
(6) is the command, and (7) is the current detection means.

Next, I will explain Sensaku. The DC power generated by the 14-inch battery Il+ is converted into AC with the same predetermined wave number by the inverter 13), and the power is supplied to the AC power system (4) of the commercial system etc. However, if the capacity of the solar cell is very small compared to the grid capacity, there will be no problem, but if the output of the solar cell is not supplied directly to the grid, the power fluctuation of the grid will occur. 'IK occurs and becomes a problem. For this reason, a storage battery (21) is usually provided in the DC circuit to temporarily store the solar cell output.

The inverter (31) detects the supplied power by the current detecting means (7).
), - In this case, since the human direct pressure is almost constant, the input current is detected by □ which is proportional to the supplied power, and the power C current) control circuit (5) is set so that this value is equal to the command value (6). controlled by

By the way, the power supply command value (6) is determined depending on the purpose of operation. For example, when load leveling is performed, it is determined by the power operation pattern based on the supply and demand relationship of the grid, but normally at night, energy is received from the grid and the storage battery is charged.
As a result, the electricity is rapidly discharged during a specific time period during the day, and the required capacity of the electricity storage j'@f21 becomes extremely large. on the other hand,
There is an operation method called power generation leveling. This is a method of suppressing sudden fluctuations in the power generated by this solar cell power supply system regardless of the supply and demand of the AC system (41), and as described above, to prevent any significant impact on the system. In this case, For the command value (6), for example, as shown in Figure 2, the expected power generation pattern of the solar cell that is initially determined is used, but the actual solar cell output is as shown in Figure 2, fBl.
Influenced by clouds and other factors, the weather fluctuates widely and often deviates much more than expected. The solar cell output ((B) in the same figure) and the power supplied to the grid (tAl in the same figure) are covered by charging and discharging the storage battery. As a result, when the instantaneous value of the difference [I] is large, the charging and waste current of the JIi battery also becomes large. Furthermore, the integral value of the difference shown in +CI in the same figure is the charging of the storage battery,
Light because it is the amount of electricity in a discharge.

If the balance of discharge is disrupted and the storage battery installed capacity h1 is not sufficient, overcharging, overdischarging, etc. will occur, and it is extremely naive to completely predict the -1 limit output, and the storage battery capacity will inevitably increase. 1 could not be prevented.

This invention belongs to power generation leveling, but was made to eliminate the drawbacks of the conventional ones as described above.It detects the output of solar cells, smooths it, and uses it as a command value for inverter output control. , Since the charging/discharging current of the storage battery becomes relatively small and the charging/discharging balance is automatically lost, the capacity of the storage battery equipment can be reduced, and a power supply system control method that can prevent sudden changes in the power supplied to the grid. It provides:

An embodiment of the present invention will be described below with reference to the drawings. 8th
In the figure, (7a) is a current detection means s provided to detect the output of the solar cell (1). (7b) is a current detection means s provided to detect the output of the inverter 13) to the AC power system (4). The current detection means (8) smoothes the output signal of the solar cell detected in (7a), and calculates the magnetic force (
Smoothing circuit (current) to set the command value to the control circuit (5)
filter), and a -order lag circuit is usually used.

Next, the operation will be explained using FIGS. 8 and 4.

Solar cells (11 examples of daily output fluctuations are shown in Figure 4)
Shown in Figure +B). Now, since the DC voltage is almost constant due to the battery voltage, it is proportional to the DC current and power as in the case of Figure 1, so the current detection means (7a) 4 (B)) is detected. This is a smoothing circuit (
If the waveform is smoothed in step 8), a smooth waveform can be obtained as shown in Fig. 4 (■). This is used as a command signal for the control circuit (5), and the current (power) of the inverter (3) is detected by the detection means (7b).
) and performs feedback control, the same power supplied to the inverter as in Fig. 4 fD) can be obtained.

The charging and discharging current to the storage battery (2) is determined by the solar battery output (Figure 4 (B)) and the inverter output (Figure 4 (D)).
If you integrate this, you will get 1! As shown in the diagram tE), the amount of electricity charged and discharged from the pond hardly changes, and if there is no loss, the final value and the initial value will be equal. These maximum amplitudes can also be determined by the time constant of the smoothing circuit (8). As a result, the amount of electricity charged and discharged from the pond can be greatly reduced, and equipment flexibility can be reduced.

In the above embodiment, the output of the solar cell is detected by the current detection means (7a)K, but if the DC voltage fluctuates, the rK force may of course be directly detected. Also, this (7
Instead of a), the amount of solar radiation that governs the solar cell output may be detected using a pyranometer, etc. Furthermore, the smoothing circuit (8) is not limited to a -order lag filter, but also has a filter that matches the solar cell output fluctuation spectrum. Keyaki's smoothing circuit can be used.

As described above, according to the present invention, in a power supply system to a grid of solar cells in which power storage 1 East is installed in parallel, the output of the solar cells is detected, smoothed, and used as a power supply command to the grid. By doing so, we can prevent sudden changes in the power supplied to the grid.
Accumulation +1. The amount of electricity charged and discharged from the L battery can be kept low, the capacity of storage battery equipment can be reduced, and the depth of discharge can be easily managed.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram showing a conventional power supply system control method, Fig. 2 is a diagram showing waveforms of each part to explain the work in Fig. 1,
FIG. 8 is a block diagram showing a method of controlling a power feeding system according to an embodiment of the present invention, and FIG. 4 is a diagram showing waveforms of various parts for explaining the supplementary work of FIG. In the figure, Ill--one solar cell, j21--one storage battery, +31--inverter, +41--one current source system, +5+--inverter's ′component C heart flow) control circuit, (7+-- −One current (one force) detection means, +8+−−
- smoothing circuit C filter). In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Agent Shin Kuzuno - Figure 1 Figure 2

Claims (1)

[Claims] (1) In a power supply system that supplies power from a solar battery and a storage battery parallel to the solar battery to another AC power source via an inverter, detecting the output or amount of solar radiation of the solar battery,
A method for controlling a power supply system, characterized in that the output of the inverter is controlled according to this value by smoothing this value.