JPS59144324A - Solar light generating device - 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] The present invention relates to a solar power generation device.

FIG. 1 shows an example of a solar power generation device in which solar cells are connected to a general power distribution system. In Figure 1, the output of the solar cell is passed through the switch to the filter capacitor, ? , connected to the inverter. The inverter converts the DC input into AC, and it is connected to the general power distribution system 7 by the switch B via the isolation transformer S, which also serves as a grid interconnection handle, and the power is supplied to the general power distribution system.

At the moment when the switch is turned on, a current Ic expressed by the following equation (1) flows through the filter capacitor 3. However,
r is the sum of the line resistance between the solar cell l and the filter capacitor 3 and the internal resistance of the filter capacitor 3.

Ed is the solar cell output voltage.

CLt Capacity of filter capacitor J This current Ic has an extremely large value because the resistance r is small, and an excessive current flows every time the switch is turned on, which shortens the life of the filter capacitor 3. Furthermore, in a system in which a battery is connected to the DC side in order to stabilize the power supply source, the IC becomes larger than in a case where only a solar cell is used. The formula fil treats the solar cell output as a voltage source, but in reality, Ic is limited because thick batteries have drooping characteristics.

However, as mentioned above (if the battery is connected, the formula fi
It depends on the calculation of +. In any case, the filter capacitor 3 is subject to a heavy burden and its lifespan is inevitably shortened.

This invention was made in order to eliminate such drawbacks, and is a solar power supply device in which the initial charging current to the filter capacitor is suppressed by providing a limiting resistor in series with the filter capacitor. It provides:

FIG. 2 shows an embodiment of the present invention. As shown in the figure, a limiting resistor g having a resistance value R and a thermal relay IO1 short-circuit contactor are connected between the switch and the filter capacitor 30. When turning on the switch, first turn off the short-circuit contactor t, and as a result, the charging current of the filter capacitor 3 flows through the limiting resistor g, so the charging current Ic' becomes as shown in the following equation 12+ .

The value R of the limiting resistor g is determined so that Ic' in equation (2) is less than or equal to the allowable ripple current of the filter capacitor 3. Since the charging time constant τ is determined by τ=RC, inrush current to the capacitor 3 can be avoided by turning on the short-circuit contactor t one second after the switch - is turned on. Since the inverter is operated after the contactor is turned on and the limiting resistance is short-circuited, the operation of the inverter is not affected in any way.

Note that the limit/resistance g is selected based on the short-time rating, so if the short-circuit contactor fails and does not turn on, it will burn out if current is passed through this resistor for a long time.Thermal relay 10 This is provided to prevent this, and if current flows for a long time, the thermal relay detects heat generation and operates, thereby stopping the inverter and preventing burnout of the limiting resistor. Furthermore, instead of the thermal relay 10, a device for detecting the voltage across the limiting resistor g may be provided, and the duration of the current exceeding a predetermined value may be detected from the change in the voltage across the limiting resistor g.

As described above, according to the present invention, since the initial charge flow is suppressed, it is possible to prevent the life of the filter capacitor 3 from decreasing.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a case in which power is supplied from a conventional solar cell to a power distribution system, and FIG. 1 is a block diagram showing a case in which power is supplied from a solar cell to a power distribution system according to an embodiment of the present invention. In the figure, l is a solar cell, λ is a switch, 3 is a filter capacitor, Hiro is an invar'p, 5
is an isolation transformer, 6 is a switch, 7 is a power distribution system, g is a limiting resistance, and t&ma. Short circuit contactor, IO indicates thermal relay. Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent Haku Kuzuno −

Claims (3)

[Claims] (1) In a solar power generation device used as an AC power source by smoothing the generated DC power obtained from a solar cell that receives sunlight and generating electricity with a filter capacitor and then converting it into AC power via an inverter, the filter capacitor is used as an AC power source. A solar power generation device comprising, on the input side, a limiting resistor for suppressing the initial charging current, and a switch connected in parallel with the limiting resistor and short-circuiting the limiting resistor after charging is completed. . (2) A patent in which a thermal relay is connected in series with the limiting resistor that operates by detecting the amount of heat generated when a current flows for a period longer than that, and the inverter is stopped by the operation of the thermal relay. The solar power generation device according to claim 7. (3) A device that operates by detecting a change in the voltage across the limiting resistor when current flows through the limiting resistor for a long time is provided, and the inverter is stopped by the operation of this device. The solar power generation device according to item 1.