JP2001197751A - Power supply using natural energy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make effective use of a power supply obtained from natural energy. SOLUTION: The output voltage of a DC/DC converter 12 supplied from a natural energy power 11 and the output voltage of a rectifier circuit 15 supplied from a commercial power supply 14 are linked and supplied to an AC load 16 through a DC/AC converter 13. At this time, the voltage outputted from the DC/DC converter 12 is previously set higher than the voltage outputted from the rectifier circuit 15. As a result, when a prescribed power (preset voltage value) is supplied from the natural energy power 11, power supplied from the natural energy power 11 is supplied to the AC load 16 and, when the power supply from the natural energy power 11 drops, power supplied from the commercial power supply 14 is supplied to the AC load 16 according to the change in the power supply.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply for effectively utilizing natural energy such as solar power and wind power.

[0002]

2. Description of the Related Art In recent years, power supply devices utilizing natural energy such as sunlight and wind power have been developed in consideration of environmental problems. However, the power generation method using natural energy has a drawback that, besides having a low energy density, the output amount due to the power generation is easily affected by weather conditions, and stable power supply cannot always be performed. Further, since the power generated by this method is a DC voltage, when power is supplied to a normally used load, DC / A
It is necessary to provide a C inverter and convert the AC voltage.
Under these conditions, power supply devices of several types have been developed to make effective use of natural energy.

FIG. 5 shows an example of a power supply device using a system link system, which is one form of a conventional power supply device. DC power obtained by solar power generation using sunlight or wind power generation using wind power (hereinafter referred to as renewable energy power)
51 is input to a DC / AC inverter 52, converted into AC power, and output. The AC power output from the DC / AC inverter 52 is input to the system linking device 53. On the other hand, the electric power output from the commercial system power supply 55 is connected to the output side of the system linking device 53. The power storage device 5
Reference numeral 4 is connected to the commercial system power supply 55, and is configured to be used as an emergency power supply when the commercial system power supply 55 is out of power. Then, electric power is supplied to the AC load 56.

FIG. 6 shows an example of a power supply device using a system switching system which is one form of a conventional power supply device. The natural energy power 61 is input to a DC / AC inverter 62 and is converted into AC power. The output AC power is
The signal is input to the switching circuit 63. In addition, power supplied from the commercial system power supply 65 is input to the switching circuit 63.
The power storage device 64 is connected to a commercial system power supply 65 and is used to supply stable power to the AC load 66 and as an emergency power supply when the commercial system power supply 65 fails. Then, the electric power output from the switching circuit 63 is supplied to the AC load 66.

FIG. 7 shows a power supply unit using an isolated operation system, which is one form of a conventional power supply unit. The natural energy power 71 is input to the DC / AC inverter 72 and is converted into AC power. Then, the power output from the DC / AC inverter 72 is supplied to the AC load 74. Note that the fluctuation of the AC load 74 and the renewable energy 71
A stable electric power corresponding to the change in the power generation amount of the AC load 74
, A storage battery 73 is connected to the input of the DC / AC inverter 72.

[0006]

However, the power supply device having the above configuration has a drawback that the cost of the system connection device 53 is high in the system link system, and is installed in all the power devices. It was difficult.
Further, in order to connect the system linking device 53, it is necessary to certify an electric power company, and the procedure is complicated, which is one of the factors that hinder the spread of this system.

In the system switching method, switching is appropriately performed by a switching circuit 63 to supply either power from the natural energy 61 or power from the commercial power supply 65 as the power supplied to the AC load 66. However, the power supplied to the AC load 66 fluctuates because there is a difference in the amount of supply from both powers at the time of this switching. Therefore, in order to supply stable power,
There is a drawback that a power storage device is required and the cost is increased. In addition, when unstable natural energy is used, the switching frequency increases, and it is necessary to improve the reliability of the switching in order to prevent an instantaneous power failure occurring at the time of the switching, resulting in an increase in cost. Was.

[0008] In the islanding operation system without system link, etc., the storage battery 73 is required to stably supply the power to the AC load 74, and the battery needs to be periodically replaced. Disadvantageously increases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and aims to stably supply power even when the load fluctuates and the fluctuation in the amount of generated natural energy without increasing the cost of the apparatus. The purpose is to provide a power supply device for natural energy that can be used.

[0010]

Means for Solving the Problems In order to solve the above-mentioned problems, a first aspect of the present invention is a power supply device using natural energy obtained by solar power or wind power as a power source. The DC power is adjusted to a DC voltage value that is higher by a predetermined voltage than a voltage obtained from a commercial power supply that has been adjusted to a predetermined DC voltage value, and the two DC voltages are connected and used. Is what you do.

According to another aspect of the present invention, a DC power obtained by renewable energy generation is adjusted to a predetermined AC voltage value by a predetermined AC voltage value more than a voltage obtained from a commercial power supply. It is characterized in that the AC voltage value is adjusted to be higher by the voltage and the two AC voltages are connected and used.

When the natural energy power supply and the commercial system power supply are connected with a DC or AC voltage, the natural energy side voltage is set higher than the commercial system side voltage and connected, so that the power on the natural energy side is reduced. It can be used in preference to the electric power on the commercial grid side, and furthermore, the power supply from the commercial grid power supply automatically increases or decreases according to the fluctuation of the load and the fluctuation of the amount of generated natural energy. .

Further, in order to solve the above-mentioned problem, the invention according to claim 3 is characterized in that the power supply device according to claim 1 or 2 is provided with a power storage facility. When the supply of power from the commercial system power supply is stopped due to a power failure or the like, the power storage equipment operates as an emergency power supply to supply power.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a power supply device for natural energy according to the present invention.

FIG. 1 shows an embodiment of a power supply device for natural energy using a DC connection method. As shown in the figure, the power supply device is a power supply device of a type in which electric power obtained by power generation of sunlight or wind power and electric power supplied from a commercial system power supply are connected by a DC voltage. Natural energy power 11 obtained by solar power generation or wind power generation is output as DC power. Since this power is easily affected by a change in load and lacks stability, the voltage is stabilized by inputting the power to the DC / DC converter 12. On the other hand, AC power supplied from the commercial system power supply 14 is rectified by the rectifier circuit 15 and its output is DC / DC.
It is input to the output side of the DC converter 12. As a result, the voltage supplied from the natural energy power 11 side and the voltage supplied from the commercial system power supply 14 side are connected by a DC voltage. When the output voltage value supplied from the commercial system power supply 14 needs to be accurate, a DC / DC converter is connected to the subsequent stage of the rectifier circuit 15.

The two connected voltages are set with a certain voltage difference. That is, the output voltage value of the DC / DC converter 12 supplied from the natural energy power 11 side is set higher than the output voltage value of the rectifier circuit 15 supplied from the commercial system power supply 14 side. Accordingly, when the voltage having the set value is supplied from the natural energy power 11 side, the power output from the DC / DC converter 12 is supplied to the DC / AC inverter 13 as the power supplied to the load. Is entered. Although it differs depending on the voltage level used, for example, for 100 V, 200 V, etc.
, The DC / AC inverter 13 is provided in the previous stage.
The degree of freedom in setting both voltage differences is increased, and as a specific example, a voltage difference of about 20 V is provided. On the contrary,
The amount of power generated by solar power or wind power decreases, and the power supplied from the renewable energy power 11 side decreases,
When the voltage value output from the DC / DC converter 12 is lower than the output voltage value of the rectifier circuit 15 supplied from the commercial system power supply 14, the insufficient power is supplied to the rectifier circuit 1.
It is configured to be supplied to the DC / AC inverter 13 from the fifth side. When the power supplied from the natural energy power 11 increases and the voltage value output from the DC / DC converter 12 becomes higher than the voltage value output from the rectifier circuit 15 by a certain voltage value again , Power from the natural energy power 11 side is supplied to the load.

The DC / DC converter 12 and the DC / DC converter
The AC inverter 13 operates within a preset input voltage range. Therefore, when the input voltage is an abnormally low voltage or an abnormally high voltage, the output is temporarily stopped, and then the operation is automatically started. For example, when the amount of power generation on the renewable energy power 11 side is greater than the amount of power consumed by the load, and when solar power generation is used as a renewable energy power source, DC / D
When the input voltage of the C converter 12 rises and exceeds a preset upper limit value of the range of the operating input voltage of the DC / DC converter 12, the output temporarily stops. When the output of the DC / DC converter 12 is stopped, the power from the rectifier circuit 15 supplied from the commercial system power supply 14 is supplied to the input of the DC / AC inverter 13. And then DC /
The operation of the DC converter 12 automatically recovers, and the output power is supplied to the DC / AC inverter 13.

When wind power generation is used as a natural energy power source, the amount of wind power generated excessively is adjusted by a regulator (not shown) provided on the wind turbine side that generates power. . That is, excessively generated power is consumed by the dummy load connected to the regulator. Therefore, even when the amount of power generated by the wind power generation is larger than the amount of power consumed by the load, the power is consumed by the dummy load, and the voltage input to the DC / DC converter 12 is within the range of the operation input voltage. In this case, the operation of the DC / DC converter 12 is not stopped, and the power is continuously supplied to the load. However, if the input voltage to the DC / DC converter 12 rises and exceeds the operation input voltage value despite the adjustment of the dummy load, the DC / DC
The operation of the DC converter 12 temporarily stops, and then automatically returns.

The DC power input to the DC / AC inverter 13 is converted to AC power and supplied to an AC load 16.

FIG. 2 shows an embodiment of a power supply device for natural energy by the AC connection system. As shown in the figure, the power supply device is a power supply device of a type in which electric power obtained by power generation of sunlight or wind power and electric power supplied from a commercial power supply are connected by an AC voltage. Natural energy power 21 obtained by solar power generation or wind power generation is output as DC power. This DC power is input to the DC / AC inverter 22, converted into AC power, and output. On the other hand, AC power supplied from the commercial system power supply 23 is input to a switching (SW) circuit 24, and the output thereof is connected to the output side of the DC / AC inverter 22. SW circuit 24 provided after commercial power supply 23
From the natural energy power 21 side to the commercial power supply 2
3 prevents the occurrence of reverse power flow. Thus, the voltage output from the SW circuit 24 and the voltage output from the DC / AC inverter 22 are both AC voltages, and both are connected by AC voltage.

The AC voltage waveform on the natural energy power 21 side output from the DC / AC inverter 22 is output in synchronization with the AC voltage waveform supplied from the commercial system power supply 23. The two AC voltage values are set in advance with a certain voltage difference. That is, the output voltage value of the DC / AC inverter 22 supplied from the natural energy power 21 side is set higher than the output voltage value of the SW circuit 24 supplied from the commercial system power supply 23 side. In the case of the AC connection method, since the voltage level supplied to the AC load 25 is adjusted, the degree of freedom in setting the voltage difference between the two becomes smaller than in the case of the DC connection method described above. It has a voltage difference of 5V. Accordingly, when the voltage having the set value is supplied from the natural energy power 21 side, the power output from the DC / AC inverter 22 is supplied to the AC load 25 and supplied from the natural energy power 21 side. If the power output from the DC / AC inverter 22 drops below the output voltage of the SW circuit 24 supplied from the commercial power supply 23, Is supplied to the AC load 25. Then, the power supplied from the renewable energy power 21 increases, and the voltage value output from the DC / AC inverter 22 becomes higher by a certain voltage value than the voltage value output from the SW flow circuit 24 again. In this case, power from the natural energy power 21 side is supplied to the load. When the supply of electric power from the commercial system power supply 23 stops due to the power failure, the output voltage of the DC / AC inverter 22 supplied from the natural energy power 21 side is supplied to the AC load 25.

In addition, setting of the operating range of the DC / AC inverter 22, or adjustment of energy by wind power generation, and the like are performed in the same manner as in the DC power supply apparatus shown in FIG.

FIG. 3 shows a configuration in which a power storage device 31 is added to the DC power supply system shown in FIG. The power storage device 31 is used as an emergency power supply when the commercial system power supply 14 fails. The set value of the output voltage of the power storage device 31 is the DC value supplied from the natural energy power 11 side.
The voltage is set to be lower than the output voltage of the / DC converter 12 and the rectifier circuit 15 by a certain voltage value, and the operation thereof performs the same function as the rectifier circuit 15 described in FIG.

FIG. 4 shows a configuration in which a power storage device 41 is added to the power supply device of the AC connection type shown in FIG. 2, and is used as an emergency power supply when the commercial system power supply 23 fails. The power storage device 41 is connected to the input side of the DC / AC inverter 22 and supplies power to the DC / AC inverter 22 when the amount of power generation on the natural energy power 21 side decreases.

Each of the power storage devices 31 and 41 attached to the above-described DC-connected or AC-connected power supply device is described for charging from the commercial system power sources 14 and 23, but is not limited to this case. Instead, the battery may be charged from the natural energy power 11 or 21 side, or may be charged from both the commercial system power supply and the natural energy power.

[0026]

As described above, the present invention provides a DC power supply system or an AC power supply system, that is, a method in which the voltage on the renewable energy generation side and the voltage on the commercial system power supply side are set to a predetermined DC voltage level or AC voltage. By adjusting the level and connecting the two, and supplying it to the load side, the shortage of power supplied from the renewable energy generation side can be reduced to the commercial system power supply side without generating reverse power flow. Thus, stable power supply can be realized without providing a high-cost system interconnection device.

Further, since the power storage device is not required in a normal use state, installation costs and maintenance costs can be reduced. Furthermore, by attaching a power storage device, it can be used as an emergency power supply.

The supply of electric power from the commercial system power supply automatically increases or decreases in accordance with the fluctuation of the load and the fluctuation of the amount of generated natural energy, so that the natural energy having a large fluctuation can be effectively used.

[Brief description of the drawings]

FIG. 1 is a diagram showing a power supply device using a DC connection system according to an embodiment of the present invention.

FIG. 2 is a diagram showing a power supply device using an AC connection system according to another embodiment different from FIG. 1;

3 is a diagram showing a power supply device in which a power storage device is added to the DC connection type power supply device shown in FIG.

FIG. 4 is a diagram showing a power supply device in which a power storage device is added to the AC connection type power supply device shown in FIG. 2;

FIG. 5 is a diagram showing a conventional power supply device based on a system link system using natural energy.

FIG. 6 is a diagram showing a conventional power supply device using a system switching method using natural energy.

FIG. 7 is a diagram showing a conventional power supply device using a single operation method using natural energy.

[Explanation of symbols]

 11 Natural Energy Power 12 DC / DC Converter 13 DC / AC Inverter 14 Commercial Power Supply 15 Rectifier Circuit 16 AC Load 21 Natural Energy Power 22 DC / AC Inverter 23 Commercial Power Supply 24 SW Circuit 25 AC Load

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5G003 AA01 AA06 AA07 BA01 DA05 DA18 GB03 GB06 5G066 BA03 HB06 HB09 JA02 JB03 5H007 BB07 CC09 CC12 GA09 5H420 BB14 CC03 CC04 CC06 DD03 DD06 EA48 EB39 EB40

Claims (3)

[Claims] 1. A power supply device that uses natural energy obtained by solar power generation or wind power generation as a power source, wherein the DC power obtained by natural energy generation is obtained from a commercial system power supply adjusted to a predetermined DC voltage value. A power supply device using natural energy by a DC connection method, wherein the DC voltage value is adjusted to a DC voltage value higher by a predetermined voltage than the applied voltage, and both DC voltages are connected and used. 2. A power supply device using natural energy obtained by solar power generation or wind power generation as a power source, wherein the DC power obtained by natural energy generation is obtained from a commercial system power supply adjusted to a predetermined AC voltage value. A power supply device using natural energy by an AC connection system, wherein the AC voltage value is adjusted to a higher AC voltage value by a predetermined voltage than the applied voltage, and the two AC voltages are connected and used. 3. The power supply device using natural energy according to claim 1, further comprising a power storage facility.