JPH04312318A - Power supply for building - Google Patents

Abstract

PURPOSE:To provide a power supply for building which can provide a load with high quality power and in which highest energy efficiency operation can be realized by facilitating supply quantity control of purchase power system and a new distributed power supply system. CONSTITUTION:A purchase power system and a new type distributed power supply system 14 such as a fuel cell, for example, are subjected to DC interconnection and a power flow controller 16 for controlling allocation of current supply between the purchase power system and the new type distributed power supply system 14 is disposed at the interconnecting section between them.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is a building power source that connects a power purchasing system from an electric utility company with a new type of distributed power system such as a fuel cell or a solar cell to supply power to loads inside a building. Regarding equipment.

0002

[Prior Art] In a typical building power supply system, power is received at high voltage from the power purchase system from an electric utility company, and the voltage is stepped down to the required voltage, for example, 210V or 105V, using a transformer, and then the power is supplied to the load. is normal. On the other hand, in recent years,
From the viewpoint of supply reliability and economic efficiency to loads, new types of distributed power generation equipment such as fuel cells and solar cells will be installed in buildings, etc., and the power purchasing system will be interconnected with this new type of distributed power generation system to supply power to loads. A power supply device that supplies power has been put into practical use.

FIG. 3 shows a conventional building power supply of this type, which is a 50/6 power supply supplied by an electric utility.
The high-voltage power purchased at 0 Hz is stepped down to a low voltage at a transformer 5 through a disconnector 1, a power supply/demand instrument transformer (MOF) 2, a circuit breaker 3, a reverse power detection protection device 4, etc., while a fuel cell 6 The DC output obtained by
z to AC, connect the power purchasing system from the transformer 5 and the new type of distributed power system from the inverter 7 outputted through the molded circuit breaker 8, and connect it through the molded case breaker 9 and the high frequency inverter 10. It is trying to supply power to the load.

0004

[Problems to be Solved by the Invention] In the conventional building power supply system described above, although the reliability of power supply to loads can be increased by interconnecting the power purchasing system and the new type of distributed power system, Since the electricity purchasing system and the new type of distributed power generation system are interconnected with AC, it is particularly susceptible to frequency fluctuations and voltage fluctuations in the electricity purchasing system, which has the disadvantage of resulting in a low-quality power source. Since the power system and the new type of distributed power system are simply interconnected, it is difficult to control the supply amount of both systems, and there are drawbacks such as high energy efficiency operation cannot be expected. Furthermore, in the event of an accident or power outage in the power purchasing system, there is a problem in that reverse power is supplied from the new type of distributed power supply system to the power purchasing system, and for this reason, there is a problem in that a reverse power detection protection device 4 must be particularly provided.

[0005] The present invention has been made in consideration of the above-mentioned problems of the conventional technology, and its purpose is to facilitate the control of the supply amount from the power purchasing system and the new type of distributed power system. An object of the present invention is to provide a power supply device for a building that can operate with maximum energy efficiency and supply high-quality power to a load.

[0006]

[Means for Solving the Problems] In order to achieve the above object, in the building power supply device of the present invention, the power purchasing system and a new type of distributed power system such as a fuel cell are connected with direct current, and the power purchasing system A power flow control device is provided at the interconnection section between the power supply system and the new type of distributed power generation system to control the distribution of the supply current from the power purchasing system and the supply current from the new type of distributed power generation system.

[0007] The building power supply device of the present invention also includes a rectifier that converts the power purchasing system into DC, a power flow control device that receives the DC output from the rectifier and the DC output from the new type of distributed power system as inputs, It is equipped with a high frequency converter that converts the DC output from the tidal flow control device into high frequency, and the DC output from the tidal flow control device and the high frequency output from the high frequency converter are respectively supplied to the load.

[0008]

[Operation] The AC output from the power purchasing system is once converted to DC output by a rectifier, and this DC output and the DC output from the new type of distributed power system are input to the power flow control device and connected to the DC output. This power flow control device controls the output distribution between the supply current from the power purchasing system and the supply current from the new type of distributed power system.
Maximum energy efficiency operation is possible by controlling the distribution between the power purchasing system and the new type of distributed power system according to energy costs, etc.

[0009]

[Example] An example will be explained using FIGS. 1 and 2. Figure 1 shows the overall configuration of the building power supply device according to the present invention, and shows the 50/60 power supply system supplied by the electric utility company.
The high-voltage power purchased at Hz is passed through a disconnector 1, a power supply and demand instrument transformer (MOF) 2, and a circuit breaker 3 to step down to a low voltage at a transformer 5, and this low-voltage output is converted into a power converter with a power flow control function. While supplying the power to the device 11, it is also supplied to the load as commercial power via the molded circuit breaker 12.

The power conversion device 11 includes a thyristor rectifier 13 that converts the AC power purchasing system output that has been stepped down by the transformer 5 into DC, a DC output from the rectifier 13, a fuel cell,
A power flow control device 16 that connects the DC output from a power storage device 15 that stores the generated power of a new kind of distributed power supply system 14 such as a solar cell, and a power flow control device 16 that connects the power flow control device 16 with a DC output from a power storage device 15 that stores the generated power of a new kind of distributed power supply system 14 such as a solar cell. It is equipped with a high frequency inverter 18 etc. that converts the outputted grid-connected output, that is, the DC output, into a high frequency,
The DC output from the tidal flow control device 16 is connected to the wiring circuit breaker 19.
The high frequency output from the high frequency inverter 18 is supplied to the load as a high frequency power source via the molded circuit breaker 20.
In combination with the commercial power source mentioned above, a variety of power sources suitable for various loads are realized.

The power flow control device 16 also controls the distribution of the supply current of the power purchasing system DC output output from the thyristor rectifier 13 and the supply current of the new type distributed power system DC output output from the power storage device 15. It has a ratio control function, and has a configuration as shown in FIG. 2, for example.

In other words, a new type of distributed power source 14 such as a fuel cell
cannot follow sudden load fluctuations, but in the CPU 21, even when load fluctuations occur, the new type of distributed power source 1
4, the allowable output value Pref that can be output at that point in time is calculated, and this allowable output value Pref is divided by the detected value Vdc of the voltage at the interconnection point output from the voltage detection voltage divider 23 in the divider 22, Obtain the output current target value Iref of the new type distributed power source 14.

On the other hand, a current detector 25 detects the actual output current of the new distributed power source 14 interconnected via a backflow prevention diode 24, and a subtracter 26 compares the target value Iref with the current detector 25. After calculating the difference with the value Idc and amplifying it with the error amplifier 27, it is added to a predetermined fixed bias in the adder 28, and this is input to the gate pulse generator 29, and the thyristor firing angle of the thyristor rectifier 13 is The output voltage of the thyristor rectifier 13 is controlled by controlling the phase of the target value Iref and the detected value Idc according to the difference between the target value Iref and the detected value Idc.

[0014] Then, the detected value Id with respect to the target value Iref
When c is small, that is, Idc<Iref,
Since the input level to the gate pulse generator 29 increases, control is performed in the generator 29 to increase the phase of the firing angle of the thyristor, and the output voltage of the thyristor rectifier 13 decreases accordingly. By suppressing the amount of supply from the electrical system, the output from the new type of distributed power source 14 can be increased accordingly. On the other hand, if Idc>Iref,
Since the input level to the gate pulse generator 29 decreases,
The phase of the firing angle of the thyristor becomes smaller, the output voltage of the thyristor rectifier 13 increases, the amount of supply from the power purchasing system increases, and the output from the new distributed power source 14 can be reduced.

In FIG. 2, 30 and 31 are a choke coil and a smoothing capacitor, respectively, which constitute a choke input type smoothing circuit and smooth the rectified output of the thyristor rectifier 13. Here, the CPU 21
If the allowable output value Pref can be set after comparing and calculating the energy costs of the power purchasing system and the new type of distributed power source system, optimal efficient operation can be achieved within the output range of the new type of distributed power source 14. becomes possible.

[0016] In the building power supply device having such a configuration, since the power purchasing system and the new type of distributed power system are interconnected by direct current interconnection with less frequency fluctuation and voltage fluctuation, it is possible to supply high quality power. Moreover, since the power flow control device 16 is provided at this interconnection point, the amount of supply from the power purchase system and the new type of distributed power generation system can be freely controlled, making it possible to operate with maximum energy efficiency. .

In addition, the power purchasing system is converted from AC/DC using the thyristor rectifier 13, and the new type of distributed power supply system is connected to DC to this system, and then DC/AC conversion is performed. There is no need to worry about supplying fault current, the conventional reverse power detection protection device can be omitted, and there is no need to supply fault current even in the event of a fault in the load system. Furthermore, commercial power supply,
Since it is possible to supply a variety of load-adaptive power sources such as DC power sources and high-frequency power sources, it is possible to efficiently supply the optimal power source to each type of load, reducing running costs.

[0018]

[Effects of the Invention] Since the present invention is constructed as described above, it produces the following effects. In the power supply device for a building according to claim 1, the power purchasing system and the new type of distributed power system are connected to a DC system, and a power flow control device is disposed in this connection section to freely control the amount of supply from both systems. This allows us to supply high-quality power with little frequency and voltage fluctuations, and by appropriately controlling the amount of supply from the power purchasing system and the new type of distributed power system, we are able to achieve the best mix of energy. This enables operation with maximum energy efficiency.

In the building power supply system according to the second aspect, the power purchasing system is converted to DC using a rectifier, and is connected to the new type of distributed power system in the power flow control device, and the DC output of this DC connection is converted into a high frequency signal. Since the converter is configured to perform high frequency conversion, in addition to the above-mentioned effects, it is possible to supply a variety of power sources including DC output from the tidal flow control device and high frequency output from the high frequency converter, making it a power source suitable for various loads. This makes it possible to reduce running costs, and also to prevent reverse power supply to the power purchasing system and supply of fault current to the load system.

[Brief explanation of drawings]

FIG. 1 is a single-line connection diagram showing one embodiment of a building power supply device according to the present invention.

FIG. 2 is a detailed block diagram of the tidal flow control device in FIG. 1.

FIG. 3 is a single-line connection diagram of a conventional building power supply device.

[Explanation of symbols]

13 Thyristor rectifier 14 New type of distributed power source 16 Tidal flow control device 18 High frequency inverter

Claims (2)

[Claims] Claim 1: A power purchasing system and a new type of distributed power generation system such as a fuel cell are interconnected with direct current, and a supply current from the power purchasing system is connected to an interconnection section between the power purchasing system and the new type of distributed power generation system. A power supply device for a building, characterized in that it is provided with a tidal flow control device that controls the distribution of the supply current from the new type of distributed power supply system. [Claim 2] A rectifier that converts a power purchasing system into DC, a power flow control device that receives the DC output from the rectifier and a DC output from a new type of distributed power supply system, and a DC output from the power flow control device. A power supply device for a building, comprising: a high-frequency converter that converts the power into a high-frequency signal, and supplies a DC output from the tidal flow control device and a high-frequency output from the high-frequency converter to a load, respectively.