JPS60170428A - Solar light generator - 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] [Technical field to which the invention pertains] This invention stores excess electrical energy generated by solar cells in a battery and a flywheel, and uses the energy stored in the battery and flywheel as needed. The present invention relates to a solar power generation device from which solar power can be extracted.

[Prior art and its problems]

The biggest drawback of power generation devices using solar cells is that the output power is not constant because sunlight is unstable.

Therefore, a common method is to provide an energy storage means such as a battery and store surplus power in the battery.

Figure 1 is a circuit diagram showing a conventional example of a solar power generation device using a battery, in which when sunlight enters a solar cell 1, the light energy is converted into direct current electrical energy. is supplied to the load 3 via the blocking diode 2, but if there is a margin in the electrical line used for. When the power required by the load 3 increases, or when the power output from the solar cell 1 decreases and f and fc become zero, such as on cloudy days or at night, the power stored in the battery 4 is released to the load 3. Therefore, electric power can be continuously supplied to the load 3 without being affected by the weather.

FIG. 2 is an output characteristic diagram of the solar cell 1 using the amount of solar radiation as a parameter, in which the horizontal axis represents the output voltage and the vertical axis represents the output current. When the amount of solar radiation is low, the output of this solar cell 1 is shown by the song #ABC, but as the amount of solar radiation increases, the output characteristic becomes curve DEF, and when the amount of solar radiation increases further, it shows the output characteristic of curve GHJ. Here, point B, point E, and point H are points where the output of the solar cell becomes maximum at each solar radiation amount, that is, the point where the product of output voltage and output current becomes maximum. A curve BEH shown by a broken line connects the operating points of the maximum output, and is a curve where the voltage is nearly constant. When the battery 4 is connected to the output of the solar cell 1 and used, the voltage of the battery 4 is also approximately constant, which is preferable. However, for example, if the amount of solar radiation is large, the solar cell 1
A large amount of power is supplied from the battery 4, but if the power consumption of the load 3 is low, this battery 4 may be overcharged, so it is necessary to connect an overcharge preventer 5 in parallel to the battery 4. be. This overcharge preventer 5 is designed to cause surplus power generated by the solar cell 1 to be consumed by a resistor, but it may also have a built-in chopper or the like to control this power consumption. be.

The conventional photovoltaic power generation device shown in FIG. This has the disadvantage that the generated power is not used effectively.

[Purpose of the invention]

It is an object of the present invention to provide a solar power generation device that is small and inexpensive, and is capable of increasing the utilization efficiency of the device by operating the solar cells at the maximum output point and effectively utilizing the power generated by the solar cells. purpose.

[Key points of the invention]

This invention supplies power to a load via a blocking diode that prevents power from flowing back to the battery, and
By connecting a battery and a VVVF inverter that outputs variable voltage and variable frequency AC power in parallel to this load, and configuring the AC power from the VVVF inverter to drive an induction motor coupled to a flywheel,
When the battery becomes overcharged, the surplus is stored in the flywheel in the form of kinetic energy, and if necessary, the induction motor is operated with regenerative braking to convert the kinetic energy stored in the flywheel into electrical energy. The purpose is to convert the energy into

[Embodiments of the invention]

FIG. 3 is a circuit diagram showing an embodiment of the present invention.

In FIG. 3, the solar cell 1 receives sunlight and generates DC power, but the power is transferred from the solar cell 1 via a blocking diode 2 that prevents power from flowing backwards from the load side to the solar cell 1. DC power is given to the load 3.

The power generated by the solar cell 1 depends on the amount of solar radiation as shown in Figure 2 above. The signal is applied to a VVVF inverter 12 consisting of a transistor. This VVVF inverter 12 is thick.

The DC power from the solar cell 1 is converted into AC power of a desired voltage and frequency, such as AC power with a constant ratio of voltage and frequency, to drive the induction motor 13. A flywheel 14 is connected to this induction motor 13 and has a speed of 2.
Kinetic energy proportional to the power is stored in this flywheel 14.

The output voltage of the solar cell 1 is detected by the voltage detector 22 as an isolated voltage actual value signal, and this voltage actual value signal and the voltage target value signal from the voltage command calculator 21 are proportional integral A control signal is input to a voltage regulator 23 which is a regulator, and a control signal is output from the voltage regulator 23 to make the deviation between the two human power signals zero. The output signal from the voltage regulator 23 is input to a voltage/frequency converter 24 and a function generator 25, and the voltage/frequency converter 24 outputs a frequency command signal, which is output from the function generator 256-. A voltage command signal is output. The frequency command signal and the voltage command signal are input to the pulse width modulation circuit 26, where they are pulse width modulated and then the base drive circuit 27
By turning on and off each transistor constituting the VVVF inverter 12 through
f: The vehicle can be operated at a desired speed.

Since the output voltage when the power generated by the solar cell 1 reaches its maximum is almost constant regardless of the amount of solar radiation, a voltage setting device that outputs a constant voltage target value signal is required as the voltage command calculator 21. However, in order to operate the solar cell 1 with higher efficiency and obtain maximum power, the second
A voltage command calculator 21 is used which outputs the characteristics of the curve BEH indicated by the broken line in the figure. This is achieved by a function generator whose output signal changes with changes in solar radiation.

When the amount of solar radiation decreases or the power flowing into the load 3 increases and the power supplied by the solar cell 1 is insufficient, the kinetic energy stored in the flywheel 14 is transferred via the induction motor 13 and the VVVF inverter 12. It is given to the load 3 as electrical energy. At this time, by controlling the VVVF inverter 12, for example, by keeping the ratio of the AC side voltage and frequency constant, the DC side voltage can be controlled to be almost constant. This allows the solar cell 1 to operate at its maximum output operating point while floating charging the battery 4.
It is also possible to operate so that the output of the solar cell 1 is maximized while uniformly charging the solar cell 1.

〔Effect of the invention〕

According to this invention, the power generated by the solar cell is given to the load, the battery, and the VVVF inverter, and the VVVF
The inverter is configured to provide alternating current power to the induction motor that drives the flywheel. In a solar power generation device constructed in this way, if there is a surplus of electricity supplied to the load, that surplus electricity is stored in the battery in the form of chemical energy or in the flywheel in the form of kinetic energy, and then supplied to the load. If there is a shortage of electric power, this stored energy is released to make up for it, but if the VVVF inverter is controlled properly, it is possible to control the DC side voltage to a constant level, and the battery can be charged using floating charge or equal charge. However, since the solar cells can be operated at their maximum output operating point, equipment and energy can be used more effectively.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram showing a conventional example of a solar power generation device.
FIG. 2 is an output characteristic diagram of a solar cell, and FIG. 3 is a circuit diagram showing an embodiment of the present invention. 1...Solar cell, 2...Blocking diode, 3...Load, 4...Battery,
5... Overcharge preventer, 11... Smoothing capacitor, 12... VVVF inverter, 1
3... Induction motor, 14... Flywheel, 21... Voltage command calculator, 22...
Voltage detector, 23... Voltage regulator, 24...
...Voltage/frequency converter, 25...Function generator, 2
6...Pulse width modulation circuit, 27...7
Figure 1 -> Output pressure

Claims (1)

[Claims] A solar cell that receives sunlight and generates DC power; a blocking diode that prevents power from flowing back to the solar cell;
A load that receives DC power from the solar cell through the blocking diode, a battery connected in parallel to the load, and a VVVF connected in parallel to the load to convert DC power into variable voltage variable frequency AC power. A solar power generation device comprising an inverter, an induction machine connected to the AC side of the inverter, and a flywheel coupled to the induction machine.