JPH11113176A - Power supply method, power supply device and control method of power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply high quality power stably regardless of the type of a load by a method wherein an AC power outputted by a private generator is once converted into a DC power to absorb and smooth a voltage fluctuation and a frequency fluctuation, and the DC power is again inverted into an AC power and supplied to the load. SOLUTION: An AC power supplied by an engine generator 1 is converted into a DC power by an A/D converter 41. After the DC power is mixed with a DC power from a solar cell 2 by a DC power mixer 42, the obtained DC power is inverted into an AC power by a D/A inverter 43 and supplied to respective loads. The results of the power consumption of the loads and the output of the solar cell which are calculated by an operation unit 47 are outputted to a main control unit 48. A control signal which commands the supplement of a power shortage is supplied to the governer of the engine generator 1 by the main controller 48. If the total power of the power from the engine generator 1 and the power from the solar cell 2 still can not meet the power demands of the loads, an output signal which commands the supplement of a power shortage from a commercial power supply 3 is supplied from the main control unit 48 and the commercial power supply is linked and starts supplying a power.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply method and apparatus, and a control method of a power supply apparatus. Power supply method and apparatus capable of supplying high-quality and stable power to a load by absorbing and smoothing the power, further supplying the load with a re-alternating current, and connecting the load with commercial power depending on the power demand of the load; and The present invention relates to a method for controlling a supply device.

[0002]

2. Description of the Related Art Commercial power is generated at a power plant and transmitted to a remote demand place by a transmission and distribution line. Power loss occurs in transmission and distribution lines, and this power loss is a social loss. In addition, commercial power has high power purchase costs, and there is a possibility of sudden power outages.

[0003] In recent years, an increasing number of business establishments have set up a generator near a demand location to cover their own power demand. Examples include suburban restaurants, convenience stores, gas stations, baths, and the like.

[0004] A common generator used in these locations is an engine generator. The capacity of the generator and its price are somewhat proportional, and in order to lower the capital investment amount,
Generally, a generator with the minimum capacity to meet the power demand is used. When a shortage of power due to a sudden increase in demand or when the generator cannot be used due to a failure or the like, power is purchased from commercial power to cope with the problem.

[0005] In recent years, solar energy power generation (solar power generation, solar thermal power generation) and wind power generation using natural energy have also been performed. Furthermore, the development of fuel cells and the like is progressing, and in addition to purchasing power from commercial power, power from these power generation devices can be used as reserve power.

[Problems to be solved by the invention]

[0006] The power output from the engine generator is not only stably supplied because it is not affected by natural conditions such as weather, and the power generation cost is low at present. However, since the frequency and voltage greatly fluctuate depending on the state of the engine, the quality of the power is not good.

[0007] Electric power output from a power generator utilizing natural energy lacks stability in supply because it is affected by the weather. In particular, power generation using solar energy has a fatal defect that power cannot be supplied at night. On the other hand, commercial power has a risk of power outage due to occurrence of a ground fault or the like and electric work, and power purchase cost is high, but power quality is good.

Therefore, considering only the power cost, all the load power is normally covered by the power from the engine generator,
It is sufficient to receive commercial power for backup.

By the way, the quality required for the power varies depending on the load. For example, such high quality power is not required for lighting and the like. However, in the case of an information management system using electronic devices such as a computer, such as a POS system (point of sales system) in a convenience store, a malfunction occurs due to a change in frequency or voltage. Of power is required.

Further, if the commercial power is superimposed on the electric power generated by the engine generator just because the power consumption of the load is increased, unsynchronized electric power may be supplied to the load. In the case of an electronic device such as a POS system, a malfunction may be caused.

The inventor of the present invention has repeatedly conducted research to stably supply high-quality power (frequency, voltage and current stability) to a load regardless of the type of load and to reduce power cost. Was completed.

Therefore, an object of the present invention is to convert all the AC power output from the private power generator to DC once to absorb and smooth voltage fluctuations and frequency fluctuations, convert it again to AC, and directly supply it to the load. Another object of the present invention is to stably supply high-quality electric power regardless of the type of load by supplying power to a load in connection with a commercial power supply.

Another object of the present invention is to provide a power supply apparatus having a plurality of power supply sources, wherein power is supplied from the plurality of power supply sources in a predetermined order according to the power consumption state of a load. To provide a power supply method and apparatus in consideration of quality and cost.

[0014]

Means of the present invention taken to achieve the above object are as follows.

In the invention of the power supply method, a method for obtaining high-quality power includes a step of converting AC power by a private AC generator into DC power, and a step of converting the DC converted power into private DC power. Combining the power from the power generator to obtain a combined DC power and converting it to AC power, and supplying the AC power alone or a commercial power to the AC power to a load. Power supply method.

In the invention of the power supply apparatus, the apparatus for obtaining high-quality electric power includes a required number of private AC generators, a required number of private DC generators, and the private AC generator. A / D that converts AC power to DC power
A converter, a composite device for obtaining composite DC power by combining the power converted to DC and the power from the private DC power generator, and a D / A converter for converting the DC power combined by the composite device to AC power And a power supply device characterized by including:

The power supply device may include a superimposing device for superimposing commercial power on the AC power converted by the D / A converter.

In the invention of the control method of the power supply device, a required number of private AC generators, a required number of private DC generators, and an A / D converter for converting AC power from the private AC generator into DC power. A D converter, a DC power combiner for obtaining combined DC power by combining the power converted to DC and the power from the private DC power generator, and converting the DC power combined by the DC power combiner to AC power Using a device including a D / A converter, superimposing means for superimposing commercial power on the AC power converted by the D / A converter, and power supply selecting means, the power consumption information of the load is transmitted to the power supply selecting means. Controlling the power supply device to output and supply power to the load in a predetermined order from the plurality of power supply sources according to the power consumption state of the load. By the way .

Function / Effect An engine generator generally used as a private power generator is not good in terms of power quality because the frequency and voltage greatly fluctuate depending on the state of the engine. However, in the present invention, all the AC power output from the private power generator is once converted to DC to absorb and smooth voltage fluctuations and frequency fluctuations, and then converted again to AC and directly supplied to a load, or connected to a commercial power supply. Since the system is supplied to the load, it is possible to prevent malfunction of an information management system using electronic devices such as a computer, such as a POS system (point of sales system). Quality power can be supplied stably.

Also, a required number of private AC generators, a required number of private DC generators, an A / D converter for converting AC power by the private AC generator into DC power, and a DC converted power A DC power combiner for obtaining combined DC power by combining the power from the private DC power generator and the DC power generator; a D / A converter for converting the DC power combined by the DC power combiner to AC power; Using a device including superimposing means for superimposing commercial power on the AC power converted by the converter and a power supply selecting means, outputting power consumption information of the load to the power supply selecting means, according to the power consumption state of the load. Since the control of supplying power from the plurality of power supply sources to the load in a predetermined order is performed, high-quality power can be obtained at low cost.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail with reference to the embodiments shown in the drawings. FIG. 1 is a block diagram of a main circuit for supplying power in a restaurant. The power supply device has three types of power sources, an engine generator 1, a solar cell 2 and a commercial power source 3.

The engine generator 1, the solar cell 2, and the commercial power supply 3 are connected to a combined power supply 4. The composite power supply 4 is connected to each of the loads 11, 1 via the composite AC supply bus 5.
2, 13, and 14. The load 11 is, for example, a general power load, and the load 12 is a microwave oven or a POS.
This is the load on electronic devices such as systems. The load 13 is a general lighting load, and the load 14 is a load of the variable transmission. The number and type of these loads will vary from establishment to establishment.

The composite power supply device 4 includes an A / D converter 41
, A DC power combiner 42, a D / A converter 43, and a power supply control device 44 as power supply selection means. A
The / D converter 41 converts AC power sent from the engine generator 1 into DC power. DC power combiner 42 is A
The DC current converted by the / D converter 41 and the DC power generated by the solar cell 2 are combined. The D / A converter 43 converts the DC power combined by the DC power combiner 42 into AC power.

The power supply control unit 44 includes a power consumption input unit 45, a storage unit 46, a calculation unit 47, and a main control unit 48. Each of the loads 11, 12, 1 is connected to the power consumption input section 45.
The power consumption of 3, 14 is input and calculated. Storage unit 4
6 stores the output of the engine generator 1, the output of the solar cell 2, and the priority of which of the engine generator 1 and the solar cell 2 is used preferentially. In this priority order, a device to which low-cost electric power is supplied is set as the first order, and the solar cell 2 which normally does not require a running cost has the first order, and the engine generator 1 and the commercial power supply 3 are in order.

The arithmetic unit 47 compares the power consumption information from the power consumption input unit 45 with the output of the engine generator 1 stored in the storage unit 46 and the output of the solar cell 2. When the power consumption of the load is smaller than the output of the solar cell 2,
An instruction to supply power only from the solar cell 2 is output from the main control unit 48, and power is supplied only from the solar cell 2. When the power consumption of the load is greater than the output of the solar cell 2, an instruction to supply power from the engine generator 1 is output from the main control unit 48, and the power supply from the engine generator 1 is performed together with the power supply from the solar cell 2. .

The AC power from the engine generator 1 is A / D
After being converted to DC power by the converter 41 and combined with the DC power from the solar cell 2 by the DC power combiner 42,
The DC power is converted into AC power by the / A converter 43 and sent to each load.

The main controller 48 outputs the result of the power consumption of the load calculated by the calculator 47 and the output of the solar cell 2. The main control unit 48 sends a control signal to the governor of the engine generator 1 to make up for the insufficient power. In this way, the engine output is controlled in accordance with the power consumption of the load to reduce waste of fuel.

If the sum of the power of the engine generator 1 and the power of the solar cell 2 does not meet the demand power of the load, an output signal supplied from the commercial power supply 3 is supplied from the main control unit 48 to the power supply switch (not shown). And the interconnection is started.

When the power demand of the load decreases, the supply of power is reduced in the reverse order. It should be noted that the terms and expressions used in the present specification are merely illustrative and not restrictive, and terms and expressions equivalent to the features described in the present specification and some of them are used. There is no intention to exclude. Further, the present invention is not limited to the illustrated embodiment, and it goes without saying that many modifications can be made within the scope of the technical idea of the present invention.

[0030]

The present invention has the above-described structure and has the following effects. (1) An engine generator, which is generally used as a private power generator, is not good in terms of power quality because the frequency and voltage fluctuate greatly depending on the state of the engine. However, in the present invention, all the AC power output from the private power generator is once converted to DC to absorb and smooth voltage fluctuations and frequency fluctuations, and then converted again to AC and directly supplied to a load, or connected to a commercial power supply. Since the system is supplied to the load, it is possible to prevent malfunction of an information management system using electronic devices such as a computer, such as a POS system (point of sales system). Quality power can be supplied stably.

(2) Also, a required number of private AC generators, a required number of private DC generators, an A / D converter for converting AC power from the private AC generator into DC power, and a DC converter A DC power combiner that obtains combined DC power by combining the obtained power and the power from the private DC power generator, a D / A converter that converts the DC power combined by the DC power combiner into AC power, Using a superimposing means for superimposing commercial power on the AC power converted by the D / A converter and a device including a power supply selecting means, outputting power consumption information of the load to the power supply selecting means, and , Power is supplied from the plurality of power supply sources to the load in a predetermined order, so that high-quality power can be obtained at low cost.

[Brief description of the drawings]

FIG. 1 is a main circuit block diagram for supplying power in a restaurant.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine generator 2 Solar cell 3 Commercial power supply 4 Composite power supply device 41 A / D converter 42 DC power composite device 43 D / A converter 44 Power supply control device 11, 12, 13, 14 Load

Claims (4)

[Claims] 1. A method for obtaining high-quality power, comprising: converting AC power from a private AC generator into DC power; combining power converted into DC with power from a private DC generator to combine the power. A power supply method, comprising: obtaining DC power and converting the DC power into AC power; and supplying the AC power alone or superimposing commercial power on the AC power to a load. 2. An apparatus for obtaining high-quality electric power, comprising: a required number of private AC generators; a required number of private DC generators; and the AC power from the private AC generator is converted into DC power. An A / D converter; a DC power combiner for obtaining combined DC power by combining the power converted to DC and the power from the private DC power generator; a DC power combined by the DC power combiner to AC power And a D / A converter for conversion. 3. A power supply device comprising superimposing means for superimposing commercial power on the AC power converted by the D / A converter. 4. A control method for obtaining high-quality electric power at low cost, comprising: a required number of private AC generators; a required number of private DC generators; An A / D converter for converting power, a DC power combiner for obtaining combined DC power by combining the power converted to DC and the power from the private DC power generator, and a DC power combined with the DC power combiner Using a device including a D / A converter for converting the AC power into AC power, superimposing means for superimposing commercial power on the AC power converted by the D / A converter, and power supply selecting means, Is output to the power supply selection means, and control for supplying power to the load in a predetermined order from the plurality of power supply sources according to the power consumption state of the load is performed by the power supply selection means. Power supply equipment Control method.