JPH1189095A - Power saving method and power saving associated system using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a noise problem and the like without the need of fitting a protection device, by associatively connecting a commercial AC system and a power system from an arbitrary power generation means, in a part where at least a commercial AC-side is converted to a waveform of pulsating current. SOLUTION: Power received from a commercial AC power source 1 is converted into pulsating power in a rectifying means 3. Pulsating power from a solar battery 11 is generated independent of the commercial AC power source 1 in synchronizing with a pulsating period from the rectifying means 3. Pulsating power generated from the power generation means is connected so that it is superimposed with pulsating power from the rectifying means 3. An AC generation means 7 which converts again pulsating power from the connection point of the rectifying means 3 and the pulsating current addition means 5 into AC power again and feeds power to a load 13 is provided. Counterflow preventing diodes 3d and 5d are provided on the output side of the rectifying means 3 and the pulsating current addition means 5 for preventing the inflow of current from the other sides.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to a technical field for reducing the power consumption of commercial AC, and more particularly to a technique suitable for easily connecting natural energy such as a solar cell to commercial AC. Things.

[0002]

2. Description of the Related Art First, a description will be given of a case where a solar cell is used as a power generating means. 6 and 7 show circuit block diagrams in the case where a commercial AC line and a solar cell are interconnected by AC. Usually, in such an interconnection, an electric power system from a solar cell and an electric power system from a commercial AC are connected in parallel, and this is also called an AC interconnection system. DC power from the solar cell 40 is supplied to the inverter 44 through the backflow prevention diode 42, converted into AC power synchronized with the commercial AC line 46, superimposed on the commercial AC line 46, and supplied to the load 48. Has become. Here, the one in FIG. 6 is referred to as “there is a reverse power flow”, and when the power generated during the sunshine becomes larger than the power consumption of the load 48, the surplus can be returned to the commercial AC line 46 in reverse. This is a standard type of residential solar cell system. On the other hand, in FIG. 7, the surplus power cannot be returned to the commercial AC line 46, and is called "no reverse power flow". These AC interconnections perform only one conversion from DC to AC, and have a relatively high efficiency. On the other hand, the one shown in FIG. 8 is a system in which DCs are interconnected, and is called a DC interconnection system, in which AC power from the commercial AC line 46 is once converted into DC by the rectifying and smoothing circuit 52, and DC from the solar cell 40 is converted. After being superimposed on the electric power, the electric power is converted into an alternating current by the inverter 44 and supplied to the load 48.

[0003]

The problems of both AC and DC interconnections will be described below with reference to embodiments of the invention, which are roughly classified into AC interconnections and DC interconnections. First, regarding the AC interconnection system, the power from the solar cell 40 is converted into AC and then connected to the commercial AC line 46.
For example, when the output quality of the commercial AC line fluctuates greatly for some reason in a short time, the influence on the power quality of the commercial AC line 46 is concerned. For this reason, when such an AC interconnection system is usually constructed, the technical standards required for the distributed interconnection interconnection power generation equipment (“Guidelines for the interconnection requirements for electric power systems (revised on October 19, 1995)” and "Technical guideline for distributed power system interconnection (JEAG9701-199)
3)), etc., it is necessary to install various protection devices (not shown) everywhere, which leads to an increase in equipment cost and an increase in man-hours at the time of installation. It also requires an authentication procedure. In addition, the inverter 44 conforming to this also needs to be provided with many additional functions, which is very expensive. Next, there are also problems such as noise.
Because of this problem, power companies have to be reluctant to spread AC interconnection systems. At present, a power supply system for general loads such as vending machines and the like for general houses is supplied to each use point after stepping down a 6600 V high-voltage distribution line to 200 V using a pole transformer. If there is a reverse power flow, of course, even if there is no reverse power flow, taking the AC connection means that the power of the same quality as that in the system of each load is likely to flow backward, and it is boosted to 6600 V by a pole transformer That is, there is a possibility of returning to the high voltage distribution line.
This means that harmonic noise and various noises generated on the load side are boosted and return to the high-voltage distribution line, and there is a concern that the quality of the electricity will be seriously affected. Also, even if it does not return to the high-voltage distribution line, the reverse power flow current carrying noise and the reverse current due to trouble flow into the other use point that the transformer on one pole handles,
It can also have a significant effect on the load there. And, if many AC interconnection systems are installed in a small area, this problem can be even greater.

As described above, the current AC interconnection system requires various administrative procedures such as an authentication procedure at the time of installation, increases the cost of protective devices and the like, and, due to concerns about the power quality, requires the use of solar cells. This can be a major obstacle in promoting power saving. In other words, in the AC interconnection, a backflow to the commercial AC line is always assumed, so that the system cannot be regarded as a mere load from the viewpoint of the commercial AC line.

On the other hand, in the DC interconnection shown in FIG.
Backflow to the commercial AC line can be reliably prevented by a diode or the like, so it can be regarded as a mere load from the viewpoint of the commercial AC line, so that there is no need for ancillary equipment such as protection devices or authentication procedures, and it is simply installed. be able to.
However, it is clear that there is a performance problem that the efficiency is reduced because the commercial AC is temporarily converted to DC and then converted again to AC. Therefore, various improvement proposals have been made so far. For example, the load of one device is divided into two parts, one is supplied by converting DC power from a solar cell into AC, and the other is supplied with commercial AC as it is. The DC power from the battery is superimposed, and the load is driven without outputting a sine wave AC such as a commercial AC after the superposition. In this specification, these two embodiments are also described as belonging to the category of DC interconnection in the sense that two AC powers are not connected at the interconnection connection point. Hereinafter, the problems will be described with reference to these two application examples.

[0006] As a first application example, there is a solar cell installation in a vending machine. This is to cover a part of the electric power of a huge number of vending machines nationwide with solar cells, and its great power saving effect is attracting attention. FIG.
FIG. 1 shows a circuit block diagram of the vending machine. This means that the vending machine 54 has a commercial load 56 and a solar cell load 5
8 and the DC power from the solar cell 40 is
On the other hand, while boosting by 0, commercial AC power is taken out from before the commercial load 56 by the bypass path 62, converted into DC by the rectifying / smoothing circuit 52, superimposed on DC power from the solar cell 40, and converted into AC again by the inverter 44. Then, it is supplied to the solar cell load 58. When the power generated by the solar cell 40 decreases at night or the like, 100% commercial AC power is supplied to the solar cell load 58 by the operation of the bypass relay 66. Therefore, in addition to the above-mentioned problems, remodeling of the vending machine 54 is required, and many problems such as an instantaneous interruption of the power supply to the solar cell load 58 when the bypass relay 66 operates before and after sunset. Have. These problems are due to the vending machine 5
This occurs because the load 4 is divided into the commercial AC side and the solar cell side. One of the factors that necessitates this division is that since the maximum load capacity of the vending machine 54 is large, the corresponding inverter becomes very expensive, and it is necessary to reduce the load on the inverter side to some extent. Because there is.

Next, as a second application example, a solar air conditioner has already been proposed. This is shown in FIG.
The configuration is as follows. After the power from the commercial AC line 46 is converted to DC by the rectifying and smoothing circuit 52 and superimposed on the DC power from the solar cell 40, the VVVF inverter 64 drives the air conditioner serving as the load 48. Therefore, the load 48 must be designed not as a normal commercial AC input type but as a dedicated machine.
The reason for this configuration is that this configuration belongs to the DC interconnection shown in FIG. 8, and in order to obtain a normal commercial AC waveform, it must be converted from AC to DC and AC, resulting in an efficiency improvement. Is lower.

[0008] As described above, the solar equipment based on the direct-current interconnection requires the modification of the load side and the design as a solar exclusive equipment, which naturally has a problem of increasing the cost.

As described above, in order to utilize the energy of a solar cell by the conventional system interconnection technology,
There are many problems, such as the influence on the power quality, the exclusive use of the load, and the cost and efficiency, and it can be seen that this is a factor that hinders the spread of solar cells.

[0010]

A problem of the AC interconnection system up to the present occurs because the AC output synchronized with the commercial AC has to be connected in the immediate vicinity of the load. If it is possible to place a connection point before the inverter, that is, upstream from the inverter when viewed from the load, only one system of the AC output from the inverter is viewed from the load. Does not occur. On the other hand, the above-mentioned DC interconnection has the connection point for interconnection on the upstream side of the inverter when viewed from the load. However, as described above, the efficiency is low, and a new design on the load side is required. The point that modification is required becomes a problem. However, since the DC output from the solar cell and the AC output of the commercial power supply must be actually combined, it can be said that no interconnection method has been proposed so far to solve all of these problems. Therefore, the inventor of the present invention establishes a connection at a point equivalent to the operation on the upstream side from the supply point of the AC power to the load, such as a DC interconnection, and distinguishes the existing / new load at a low cost. It can be installed easily without any modification on the load side, and without the need for special procedures such as special certification based on the above technical standards or the installation of protective equipment, and no problems such as noise will occur. A power-saving method based on a new interconnection method that does not belong to interconnection or DC interconnection and a power-saving interconnection system using it were proposed. This method can solve the above-mentioned current problems.

[0011] Such a problem can be solved by a "power saving method in which a commercial AC system and a power system from an arbitrary power generation means are interconnected at least in a portion where the commercial AC side is subjected to pulsating flow conversion". . Specifically, `` converting commercial AC power to pulsating power, superimposing pulsating power from the power generation means synchronized with the pulsating cycle of the pulsating power on the converted pulsating power, A power saving method that converts the superimposed pulsating power into AC power and then supplies the AC power to a load, or a method that converts commercial AC power into pulsating power, and generates A power obtained by superimposing the DC power from the pulse power modulated by the pulse width modulation synchronized with the pulsating cycle of the pulsating power, converting the superimposed pulsating power into AC power, and then supplying the AC power to a load. '' Or `` Convert commercial AC power to pulsating power, superimpose DC power from the power generation means on the converted pulsating power, convert this superimposed power to AC power, and supply it to the load It is preferable to adopt a “power saving method”. In each of the above power saving methods, there is a description that "one of the commercial AC lines is shunted by a shunt channel using current limiting elements connected in parallel in opposite directions, and a positive pulsating flow flowing through each shunt channel. Based on the voltage characteristics of both ends of the current limiting element due to the negative pulsating flow, the power from the power generation means having the same polarity as the pulsating flow flowing through each branch flow path is superimposed on the pulsating flow and then the positive side again. It is more preferable to use a "power saving method of obtaining AC power by combining the negative sides". Here, since this is a solution to the above-described problem, it is preferable to use a solar cell as the power generation means.

Next, a novel power-saving interconnection system that can be constructed by using the above-mentioned method includes a rectifier for converting power received from a commercial AC power supply into pulsating power, a pulsating cycle from the rectifier, and a pulsating cycle. Synchronously, pulsating power from the power generating means is generated independently of the commercial AC power supply, and the generated pulsating power from the power generating means is connected to be superimposed on the pulsating power from the rectifying means. A device including a pulsating flow adding unit and an AC generating unit that reconverts pulsating electric power from a connection point between the rectifying unit and the pulsating flow adding unit into AC power and supplies power to a load ”
Can be realized by Here, considering the use of the solar cell, `` pulse flow adding means, at least, a solar cell as a power generating means, maximum output control means for extracting the maximum generated power of the solar cell, and DC power from the solar cell from the rectifying means And a pulsating flow converting means for converting the pulsating current into a pulsating power synchronized with the pulsating cycle of the pulsating cycle. It is composed of an optimal output control means for taking out and a pulsating current converting means for converting the DC power from the solar cell into a pulsating power synchronized with the pulsating cycle from the rectifying means. Is larger than the maximum output power of the solar cell by the optimum output control means, and if the power consumption of the load is smaller than the power generation of the solar cell, the optimum output control means Therefore preferably a thing "to the output from the solar cell can be suppressed.

[0013] Next, as another power saving interconnection system,
`` Rectifying means for converting the power received from the commercial AC power supply into pulsating power, and pulse width-modulating the DC power from the power generating means to synchronize the power synchronized with the pulsating cycle from the rectifying means from the commercial AC power supply. Pulsating flow adding means connected so that the generated power from the power generating means can be superimposed on the pulsating power from the rectifying means, and a pulse from a connection point between the rectifying means and the pulsating flow adding means. And an AC generator for re-converting the flowing power into AC power and supplying power to the load ”. Again, taking into account the use of a solar cell, the pulsating flow adding means divides at least the solar cell as the power generating means, the maximum output control means for extracting the maximum generated power of the solar cell, and the rectifying means from the DC power from the solar cell. And a modulating means that performs pulse width modulation in synchronization with the pulsating cycle of the pulsating current. ”And“ Pulling current adding means at least extracts a solar cell as a power generating means and an optimal power generated by the solar cell. It is constituted by output control means and modulation means for performing pulse width modulation in synchronism with the pulsating cycle from the rectifying means for DC power from the solar cell, and when the power consumption of the load is larger than the power generated by the solar cell. The maximum output power of the solar cell is extracted by the optimal output control means, and when the power consumption of the load is smaller than the power generation of the solar cell, the optimal output control means Preferably a thing "the output from the battery is suppressed.

As another power saving interconnection system,
`` Rectifying means for converting power received from a commercial AC power supply into pulsating power, pulsating adding means connected so that DC power from the power generating means can be superimposed on pulsating power from the rectifying means, And an AC generation means for re-converting the electric power from the connection point of the means and the pulsating flow adding means into AC power and supplying the AC power to the load.

For a power outage, a "self-excited oscillator synchronized with the commercial AC power supply is provided. When the power supply from the commercial AC power supply is cut off during power supply to the load, the power generated by the power generation means and the load of the load are reduced. The power consumption is compared with the power consumption, and when the power generated by the power generation means is equal to or greater than the power consumption of the load, the AC power having a cycle synchronized with the signal from the self-excited oscillator is continuously output from the AC generation means. With power outage control means. "
In order to further increase the safety factor in the event of a power outage over a longer period of time, a configuration in which an electric double layer capacitor is connected in parallel with the power generation means, or a configuration with a charge / discharge control circuit in parallel with the power generation means Connected to a storage battery "is more preferable.

Next, the operation of the present invention will be described. When the commercial AC power is converted to pulsating power and the power from the power generation means is superimposed on the converted pulsating power, the power is upstream from the final AC output point to the load (in the conventional interconnection system). ,
An effect equivalent to placing a connection point for interconnection on the upstream side of the inverter when viewed from the load) can be obtained. That is, by converting the superimposed pulsating power to AC power and then supplying the AC power to the load, the above-described noise problem,
Even if there is a large load fluctuation in a short time, a large output fluctuation on the power generation means (solar cell) side, or other troubles, backflow can be easily prevented by a diode etc. because of the pulsating flow. No backflow into the commercial AC line will occur since the system itself will act as a buffering and protection function. Therefore, in operation, similar to DC interconnection,
From a commercial AC line perspective, the system can be considered a load. Although the present description is about claim 1, it is needless to explain again that the same effect is obtained for claims 2 to 4.

Next, the operation of claim 5 will be described.
By shunting one of the commercial AC lines by way of a shunt using current limiting elements connected in parallel in opposite directions,
The AC positive current and the negative current flow in different branch channels. Therefore, the current flowing through each of the branch channels becomes a pulsating current, and a pulsating current is created from the commercial alternating current. Then, a voltage is generated at both ends of the current limiting element due to the positive pulsating flow and the negative pulsating flow flowing in each of the branch channels. By observing the voltage characteristics at both ends, it is possible to know in which direction the current flows in which branch channel, and this voltage change can be used as a synchronizing signal of the pulsating cycle from the commercial AC line. . In such an operation, when an output from, for example, a solar cell having the same polarity as that of the pulsating flow flowing in the same dividing flow path is superimposed on the pulsating flow, the commercial AC The electric power from the solar cell is superimposed in synchronization with the pulsating flow from the solar cell. Obviously, if the powers superimposed on the positive side and the negative side are combined again, the waveform returns to the AC waveform. If the output from the power generation means such as a solar cell is converted into a pulsating flow in advance and then superimposed as in claim 2, in principle, the sine wave equivalent to the input waveform can be obtained without performing any special processing after the synthesis. You can get the waves. When the DC output from the power generating means is superimposed in a pulse width modulated state as in claim 3, for example, it may be passed through a filter or the like after the synthesis, and as in claim 4, the DC output is superimposed as it is. in case of,
For example, a process such as pulse width modulation or a filter may be performed after the synthesis.

Then, regarding the power saving interconnection system,
Such a method / action is realized by a combination of devices and circuits. Here, if an electric double-layer capacitor or a storage battery is used, these functions as a stable DC power supply even when the output from the power generation means is lost.

[0019]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the contents and functions of a power saving interconnection system based on the power saving method of the present invention in principle. In the illustrated example, the rectifier 3 converts the power received from the commercial AC power supply 1 into pulsating power, and the pulsating current from the power generator (solar cell 11) is synchronized with the pulsating cycle from the rectifier 3. A pulsating flow adding unit 5 that generates power independently of the commercial AC power supply 1 and is connected so that the generated pulsating power from the power generating unit can be superimposed on the pulsating power from the rectifying unit 3; A power-saving interconnection system 9 including an AC generator 7 that reconverts pulsating electric power from a connection point between the rectifying unit 3 and the pulsating flow adding unit 5 to AC power and supplies the AC power to the load 13. Backflow prevention diodes 3d and 5d are provided on the output sides of the rectifying means 3 and the pulsating flow adding means 5, respectively, in order to prevent the flow of current from the other. That is, since the connection is established by the pulsating flow, the backflow between the rectifying means 3 and the pulsating flow adding means 5 can be prevented by the diode. However, in the relationship between the rectifying means 3 and the pulsating flow adding means 5 as described later (FIG. 2), it goes without saying that the backflow prevention diodes 3d and 5d need not be separately provided. If this is a conventional AC interconnection, backflow cannot be easily prevented by a diode or the like. For this reason, when installing the power saving interconnection system of the present invention, it is not necessary to attach a special protection circuit or the like.

Here, a more detailed description will be given using a simple circuit diagram. FIG. 2 is a principle explanatory diagram simply depicting a circuit configuration of an interconnection connection point due to a pulsating flow. In the illustrated example, one of the commercial AC lines 23 is divided into two by flow branches 27a and 27b using current limiting elements (diodes) 25a and 25b connected in parallel in opposite directions to each other.
1 from the booster means 29a and 29b and the control means 31
The two flow paths 27a and 27b are connected at points A while being connected to the flow paths 27a and 27b via a and 31b. Reference numeral 23b is the other of the commercial AC lines 23. Hereinafter, the basic operation will be described with reference to FIG.

The commercial AC line 23 is supplied with a sine wave AC as shown in FIG. Therefore, the branch channel 27
A pulse flow as shown in (b) in the figure flows into a, and a pulse flow as shown in (c) in the figure flows into the branch channel 27b. Thus, both ends of the diodes 25a and 25b are
Since a predetermined voltage is generated according to the pulsating current, the voltage is detected by the control means 31a and 31b, and when the current flows through the branch flow path 27a, the output of the solar cell from the boosting means 29a is controlled by the control means. The pulsating flow is superimposed by the switching operation of 31a and the like. On the other hand, when a current is flowing through the branch channel 27b, the output of the solar cell from the booster 29b side is changed by the switching operation of the controller 31b or the like.
Similarly, it is superimposed on the pulsating flow. Thus, the solar cell 11
Are superimposed on each other, the two branch channels 27a, 27
The output from b is synthesized at the connection point A, and is again supplied to the load as a sine wave AC same as that at the time of input, as shown in FIG. This example is an example in which the DC output of the solar cell 11 is converted into a pulsating flow by the control means 31a, 31b and the like, and is then superimposed on the pulsating current from the commercial AC.
In the case where pulse width modulation is performed on the output from the solar cell 11 or when the output is superimposed with a DC output, a sine wave AC may be adjusted downstream of the connection point A (on the load 13 side), for example. .

According to such a principle, the circuit configuration can be simplified, and the output of the solar cell 11 decreases to
Even when switching to 00% commercial AC consumption, no instantaneous interruption occurs in principle. In the illustrated example, the diodes 25a,
25b corresponds to the rectifying means 3 in FIG.
a, 29b and the control means 31a, 31b
In addition, the branch paths 27a and 27b and the connection point A correspond to the AC generation means 7, respectively.

Step-up means 29a, 29b, control means 31
Although the specific contents of the pulsating flow adding means 5 including the functions a and 31b are not shown here, the solar cell 1
1 (power generation means), maximum output control means for extracting the maximum generated power of the solar cell 11, and pulsating flow for converting DC power from the solar cell 11 into pulsating power synchronized with the pulsating cycle from the rectifying means 3. What is necessary is just to comprise by conversion means. This is because it is preferable to always take out the output from the maximum operating point of the solar cell 11 from the viewpoint of power saving. Therefore, such a configuration should be adopted when the maximum output of the solar cell 11 is surely smaller than the power consumption of the load 13. Separately, in order to further enhance the power saving effect, a solar cell 11 having an output larger than the maximum power consumption of the load 13 may be combined. In this case, the solar cell 11 ( Power generating means), an optimal output control means for extracting the optimal generated power of the solar cell 11, and a pulsating flow converting means for converting the DC power from the solar cell 11 into a pulsating power synchronized with the pulsating cycle from the rectifying means 3. When the power consumption of the load 13 is larger than the power generated by the solar cell 11, the maximum output power of the solar cell 11 is extracted by the optimum output control means. Is smaller than the generated power of the solar cell 11 by the optimal output control means.
What is necessary is just to include the circuit structure which suppresses the output from. Note that these configurations have the same configuration content regardless of whether DC power from the solar cell 11 (power generation means) is superimposed by pulse width modulation or superimposed as it is.

In consideration of the operation of the power-saving interconnection system 9, depending on the type of the load 13, it is necessary to consider the case where the commercial AC power supply 1 experiences a power failure. In such a case, the boosting means 29a, 2
9b and the pulsating flow adding means 5 including the functions of the control means 31a and 31b are provided with a self-excited oscillator (not shown) synchronized with the commercial AC power supply 1, and the pulsating flow adding means 5 supplies power to the load 13. When the power supply from the commercial AC power supply 1 is interrupted, the generated power of the solar cell 11 (power generation means) is compared with the power consumption of the load 13, and the generated power of the solar cell 11 is equal to the power consumption of the load 13. If it exceeds or exceeds, the power supply control unit (not shown) also has a function of a power failure control unit (not shown) capable of continuously outputting AC power of a cycle synchronized with a signal from the self-excited oscillator from the AC generation unit 7. You can also put it. Of course, this power failure control means can be separately provided without being integrated with the pulsating flow adding means 5. In the case of employing such a power failure control configuration, it is preferable to use a solar cell 11 (power generation means) having an average power generation output larger than the maximum power consumption of the load 13 in order to increase the safety factor.

Further, when it is desired to minimize the output (area in the case of the solar cell 11) of the power generating means and prepare for an instantaneous power failure, as shown in FIG. It is preferable to adopt a configuration in which the electric double layer capacitor 15 is connected. This is to charge the electric double layer capacitor 15 with a part of the output from the solar cell 11 at the time of sunshine, and to discharge and supply the charged electric charge to the load 13 at the time of an instantaneous power failure. In the illustrated example, a backflow prevention diode 17 is connected in series with the solar cell 11 in order to prevent the backflow to the solar cell 11. If it is desired to prepare for a longer-term power failure, as shown in FIG. 5, the charge / discharge control circuit 19 and the storage battery 21 may be connected in parallel with the solar cell 11 (power generation means). Similarly to the above, the storage battery 21 is charged with a part of the output from the solar cell 11 during sunshine, and the charged power is discharged and supplied to the load 13 for a long time during a power failure. Here, a backflow prevention diode 17 is connected in series with the solar cell 11 in order to prevent the backflow to the solar cell 11. Such a configuration can be used as an uninterruptible power supply using the solar cell 11.

The embodiment as described above supplies the power generated by the solar cell to the load in addition to the commercial AC power supply during sunshine, and is particularly suitable for a continuous load in the daytime.
Possible applications include the aforementioned vending machines, public telephones, traffic lights, power supplies for continuous operation of various industrial equipment, power supplies for daytime lighting in office buildings, general household appliances such as refrigerators, and other loads. It is valid. For example, when used as a power supply for vending machines or public telephones, this interconnection system is housed in one box, the AC output is turned into a female outlet, and the AC outlet plug of the existing load is simply inserted. , A power-saving interconnection system can be constructed very easily. Here, when the present invention is applied to a daytime lighting power supply in an office building, the AC generator 7 in FIG. 1 is a high-frequency inverter for lighting, and a dimming control signal corresponding to the power generated by the solar cell 11 is added. It is supplied from the means 5 to a high frequency inverter (expressed as AC generating means 7 in the figure), and the fluorescent lamp for illumination (expressed as load 13 in the figure) is turned on at a frequency and a duty (that is, electric power) according to the generated power at that time. What is necessary is to control. Most of current office building lighting is ON / OFF controlled, so it can be said that power loss is very large even in bright daylight. According to the present invention, by adding the power of the solar cell and obtaining dimming control illumination corresponding to the intensity of sunlight at that time, efficient power saving can be achieved while maintaining a comfortable office environment.

In the above embodiment, during the sunshine when the effective output from the solar cell 11 is secured, the power from the pulsating flow adding means 5 is surely superimposed on the power from the rectifying means 3 so that the power from the rectifying means 3 is superimposed. Needless to say, it is only necessary to monitor and control the voltage. As the power generation means, in addition to the solar cells exemplified here, wind power generators, tidal power generators, other gas and diesel generators, and the like, may be used singly or in combination.

[0028]

The present invention is completely different from the concept of "interconnection at the nearest connection point of the load by the AC output synchronized with the commercial AC" as in the AC interconnection system up to the present. Is temporarily converted to pulsating power, and the power from the power generation means is superimposed on the converted pulsating power. The connection can be made at the point where the action becomes. That is, from the viewpoint of the load, only one system of the AC output from the present system (AC generating means) can be regarded as a mere load on the commercial AC line. Therefore, noise problems, large load fluctuations within a short time, large output fluctuations on the power generation means side such as solar cells, and other troubles, which have been a problem in parallel interconnection to commercial AC lines, have been encountered. Even if this occurs, the present system itself will function as a buffering and protection function, so that the above-mentioned conventional problems can be solved at once.

As described above, since problems assumed in the conventional interconnection system cannot occur, various protection devices and certifications based on technical standards required for the distributed interconnection interconnection power generation equipment are not required. In addition, as can be seen from the fact that the final output is the same sine wave alternating current as the commercial alternating current and that the pulsating flow can be generated and interconnected by the simple current limiting element as described in the embodiment, It can be installed easily at no cost, without any distinction between existing and newly installed loads, without any modification on the load side. For example, if this interconnection system is housed in one box and the AC output is a female outlet, and the AC outlet plug of the existing load is simply plugged in, the power-saving interconnection system is very simple. Can be built. That is, from the viewpoint of efficiency, since the current is returned to the alternating current through the pulsating flow without generating the direct current from the alternating current, the efficiency is greatly improved as compared with the direct current interconnection, and the loss of the commercial power is extremely reduced. In addition, since this interconnection system can be operated with or without power generation means, for example, a terminal for connecting the output line of a solar cell is provided, and a configuration as "solarized equipment" is adopted. Can also. Of course, the power generation means is not limited to a solar cell. Therefore, it is possible to simply and additionally install only the external power generation means such as a solar cell at a low cost when necessary.

In addition, when used together with an electric double-layer capacitor and a storage battery, the power supply becomes excellent as a backup power supply in the event of a power failure. If an inverter for lighting is used as an AC generation means, the power supply for lighting has a high power saving effect. . In other words, the interconnection system of the present invention has both the high efficiency of the conventional AC interconnection system (FIGS. 6 and 7) and the safety of the DC interconnection system (FIGS. 8 to 10). It can be said.

As described above, the present invention renews the conventional common sense that the output from the power generation means, particularly the DC output of a solar cell or the like, and the AC output of the commercial power supply are combined at one of them. This is based on a completely new concept that does not belong to any conventional interconnection system, that is, to establish connection in the form of pulsating flow of commercial AC. As a result, as described above, all of the convenience, safety, economy, versatility, and high efficiency that have never existed before can be satisfied. Therefore, it can be effectively used as greatly useful for promoting power saving by solar cells.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically showing the contents and functions of a power saving interconnection system based on a power saving method of the present invention.

FIG. 2 is a principle explanatory diagram simply illustrating a circuit configuration of an interconnection point due to a pulsating flow.

FIG. 3 is a waveform chart for explaining a basic operation.

FIG. 4 is an explanatory diagram showing a connection example of an electric double layer capacitor in the interconnection system of the present invention.

FIG. 5 is an explanatory diagram showing a connection example of storage batteries in the interconnection system of the present invention.

FIG. 6 is a configuration diagram of a conventional interconnection system with an AC interconnection reverse power flow;

FIG. 7 is a configuration diagram of a conventional interconnection system without an AC interconnection reverse power flow.

FIG. 8 is a configuration diagram of a DC interconnection in a conventional interconnection system.

FIG. 9 is a circuit block diagram of a conventional solar cell type vending machine.

FIG. 10 is a circuit block diagram of a conventional solar air conditioner.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Commercial AC power supply 3 Rectification means 3d, 5d, 17, 42 Backflow prevention diode 5 Pulsating flow addition means 7 AC generation means 9 Power saving interconnection system 11, 40 Solar cell 13, 48 Load 15 Electric double layer capacitor 19 Charge / discharge control Circuit 21 Storage battery 23, 46 Commercial AC line 23a One of commercial AC line 23b The other of commercial AC line 25a, 25b Current limiting element (diode) 27a, 27b Dividing channel 29a, 29b Boosting means 31a, 31b Control means 44 Inverter 52 Rectification smoothing Circuit 54 Vending machine 56 Commercial load 58 Solar cell load 60 Boost circuit 62 Bypass path 64 VVVF inverter 66 Bypass relay

Claims (16)

[Claims] An electric power saving method in which a commercial AC system and an electric power system from an arbitrary power generation means are connected to each other at least at a portion where the commercial AC side is subjected to pulsating flow conversion. 2. The commercial AC power is converted into pulsating power, and pulsating power from a power generation means synchronized with a pulsating cycle of the pulsating power is superimposed on the converted pulsating power. The power saving method according to claim 1, wherein the superimposed pulsating power is converted into AC power and then supplied to a load. 3. The commercial AC power is converted into pulsating power, and the converted pulsating power is subjected to pulse width modulation in synchronism with the pulsating cycle of the pulsating power of DC power from a power generator. The power saving method according to claim 1, wherein the obtained power is superimposed, and the superimposed pulsating power is converted into AC power and then supplied to a load. 4. The commercial AC power is converted into pulsating power, DC power from a power generating means is superimposed on the converted pulsating power, and the superimposed power is converted into AC power and applied to a load. The power saving method according to claim 1, wherein the power is supplied. 5. One of the commercial AC lines is diverted by diverting channels using current limiting elements connected in parallel in opposite directions to each other, and a positive pulsating flow and a negative pulsating flow flowing through the respective diverting channels. Based on the voltage characteristics at both ends of the current limiting element, the power from the power generation means having the same polarity as the polarity of the pulsating flow flowing through each branch flow path is superimposed on the pulsating flow, and then the positive side and the negative side are combined again. The power saving method according to any one of claims 1 to 4, wherein AC power is obtained. 6. The power saving method according to claim 1, wherein a solar cell is used as said power generating means. 7. A rectifier for converting electric power received from a commercial AC power supply into a pulsating electric power, and a pulsating electric power from the power generating means synchronized with a pulsating cycle from the rectifying means, independent of the commercial AC power supply. And a pulsating flow adding means connected such that the generated pulsating power from the power generating means can be superimposed on the pulsating power from the rectifying means; and An electric power saving interconnection system comprising: an AC generator that converts pulsating power into AC power and supplies power to a load. 8. A pulsating flow adding means for synchronizing at least a solar cell as a power generating means, a maximum output control means for extracting maximum generated power of the solar cell, and a DC power from the solar cell with a pulsating cycle from the rectifying means. The power-saving interconnection system according to claim 7, further comprising: a pulsating current converting unit configured to convert the pulsating current into pulsating electric power. 9. A pulsating flow adding means for synchronizing at least a solar cell as a power generating means, an optimum output control means for extracting optimum power generated by the solar cell, and a DC power from the solar cell with a pulsating cycle from the rectifying means. And a pulsating flow converting means for converting the pulsating power into a converted pulsating power.If the power consumption of the load is larger than the generated power of the solar cell, the maximum output power of the solar cell is extracted by the optimal output control means, and If the power consumption is smaller than the power generated by the solar cell,
The power-saving interconnection system according to claim 7, wherein the output from the solar cell is suppressed by the optimum output control means. 10. A rectifier for converting power received from a commercial AC power supply into pulsating power, and a pulse width modulated DC power from the power generating means to convert power synchronized with the pulsating cycle from the rectifier into commercial AC power. A pulsating flow adding unit that is generated independently from the power supply, and is connected so that the generated power from the power generating unit can be superimposed on the pulsating power from the rectifying unit,
An electric power saving interconnection system comprising: an AC generation unit that reconverts pulsating power from a connection point between a rectifying unit and a pulsating flow adding unit to AC power and supplies power to a load. 11. A pulsating flow adding means for synchronizing at least a solar cell as a power generating means, a maximum output control means for extracting maximum generated power of the solar cell, and a DC power from the solar cell with a pulsating cycle from the rectifying means. The power-saving interconnection system according to claim 10, further comprising a modulation unit that performs pulse width modulation. 12. A pulsating flow adding means for synchronizing at least a solar cell as a power generating means, an optimum output control means for extracting optimum generated power of the solar cell, and a DC power from the solar cell with a pulsating cycle from the rectifying means. When the power consumption of the load is larger than the power generation of the solar cell, the maximum output power of the solar cell is extracted by the optimum output control means, and the power consumption of the load is obtained. 11. The power-saving interconnection system according to claim 10, wherein when the power is smaller than the power generated by the solar cell, the output from the solar cell is suppressed by the optimal output control unit. 13. A rectifying means for converting power received from a commercial AC power supply into pulsating power, and a pulsating flow connecting means connected so that DC power from the power generating means can be superimposed on pulsating power from the rectifying means. A power-saving interconnection system, comprising: means for converting power from a connection point between the rectifying means and the pulsating flow adding means into AC power to supply power to a load. 14. A self-excited oscillator synchronized with a commercial AC power supply, and compares the generated power of the power generation means with the power consumption of the load when power supply from the commercial AC power supply is interrupted during power supply to the load. Power generation control means for continuously outputting AC power of a cycle synchronized with a signal from the self-excited oscillator from the AC generation means when the power generated by the power generation means is equal to or greater than the power consumption of the load. The power-saving interconnection system according to any one of claims 7 to 13. 15. The power-saving interconnection system according to claim 7, wherein an electric double layer capacitor is connected in parallel with the power generation means. 16. The power saving interconnection system according to claim 7, wherein a charge / discharge control circuit and a storage battery are connected in parallel with the power generation means.