JP2003235162A - Power supply system and its control method - Google Patents

Abstract

(57) [Abstract] [Problem] Load fluctuation is large in small-scale power demand such as homes.
For this reason, when a power generation device such as a fuel cell and a storage battery are used in combination with an electric power system, the startup characteristics of the fuel cell are not sufficient with respect to a sudden change in load, and it has been difficult. In addition, since power generation of the fuel cell is performed irrespective of load fluctuation, there is also a problem in terms of battery life. For this reason, the realization of a power supply system capable of supplying power in accordance with the load power has been an issue. Kind Code: A1 A supply current or supply power to a plurality of loads is detected, and this is fed back to a control device. The control device detects the power generation status of the fuel cell and the operation status of the power conversion device, and controls so as to generate and supply the required power required by the load device. Further, power demand fluctuation of each load is predicted, control is performed so as to secure necessary supply power, and a capacitor is provided to respond to pulse-like peak demand.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply system having a power generator and a power storage device and a control method thereof.

[0002]

2. Description of the Related Art When a conventional distributed generator is introduced into a small-scale power consumer such as a household, the above-mentioned generator alone cannot cover the load imbalance and temporary load fluctuation depending on the time of day. Inevitably, there was no choice but to rely on an external power system such as a power company, and there was a limit to the reduction of power costs. FIG. 3 shows an example in which a storage battery is used to cope with such power load fluctuation. As shown in FIG. 3, when the fuel cell 1 and the storage battery 2 are used together, when the power demand is small, the surplus power of the fuel cell 1 is charged in the storage battery 2 via the power conversion device 4, and the power demand increases. The power supply can be supplemented by discharging the storage battery 2. Therefore, by controlling the charge / discharge amount of the storage battery 2, it becomes possible to reduce the power reception from the power system 6 which is the power supply source from the outside to zero.

However, since the fuel cell, which is a power generator, takes a long time to start up and has a slow response when the amount of power generation is changed, it is necessary to follow the load when the load electric power fluctuates greatly with time, such as at home. It is difficult to control the power generation amount of a fuel cell. Further, if the amount of power generation of the fuel cell is changed more frequently than necessary, there is a possibility that the reformer in the fuel cell system has poor responsiveness, resulting in wasteful consumption of fuel or shortened life. .

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a load device for a power supply system that rapidly supplies power to a load having a so-called large time variation, such as a sudden load variation. An object of the present invention is to provide a power supply system and a control method thereof that can stably control the amount of power generation of a power generation device and reduce the load on the power generation device by using information.

[0005]

In order to achieve the above object, a power supply system according to the present invention is, in claim 1, a power generation device, a storage battery, a storage battery such as a capacitor, a power conversion device, and a control device. And a power system, and is configured to supply power to a plurality of load devices. Here, the plurality of load devices is a load device group including a unit that detects information about the usage status or power consumption of each load device and a unit that transmits the detected information. The control device receives means for receiving information on the usage status or power consumption of each load device transmitted from the load device group, and based on the received information, the power generation amount of the power generator and the storage battery And a unit for controlling the amount of charge and discharge, wherein the power conversion device transmits and receives information to and from the control device, and a power conversion converter corresponding to each of the power generation device and the storage battery. When,
It is composed of an inverter for supplying electric power to the plurality of load devices, a terminal connected to a capacitor such as a capacitor for coping with a sudden load power fluctuation having a pulsed peak, a terminal connected to a power system, and the like. There is.

[0006] Next, as a method for controlling the power supply system according to the present invention, in the power supply system according to claim 1, a prescribed time determined by the control response of the power generator with respect to an average usage time of each of the load devices. , And the ratio of the peak power consumption to the base power which is the minimum power consumption of the power consumption is a predetermined value, that is, the rated power is also divided into two types, large and small. For each load device connected to the power converter, control the power generation amount of the power generator for the load device whose average usage time is more than this specified time and power consumption fluctuation is less than the specified ratio, and average For load devices that have a static usage time of less than the specified time and power consumption fluctuations of less than the specified ratio, the charge / discharge amount of the storage battery is controlled, and the power consumption fluctuation is the specified ratio. It is a method corresponding with the discharge or the power system of the storage battery, such as the capacitor for more load devices.

Further, in the power supply system according to the first aspect, each load device is divided into two types according to a prescribed time determined by the response of the power generation device with respect to an average usage time, and a temporal fluctuation pattern of power consumption. Is decomposed into a base component and a fluctuation component, and for each load device used,
For the base portion of the load device whose average usage time is the specified time or more, the power generation amount of the generator is controlled, and for the base portion of the load device whose average usage time is the specified time or less As a method, the amount of charge and discharge of the storage battery is controlled, and the fluctuation of the power consumption over the base amount is dealt with by discharging the capacitor such as a capacitor or the power system.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The basic configuration of an embodiment of the present invention is shown in FIG. As shown in FIG. 1, a fuel cell 1 serving as a power generator, a storage battery 2, a capacitor 3 serving as a power storage device, a power converter 4 connected to them, and a controller 5 are included. As the power generation device, a gas turbine or the like may be used in addition to the fuel cell 1 (hereinafter collectively referred to as the fuel cell 1), and the capacitor 3 may be an electric double layer capacitor. The power conversion device 4 is connected to the output of the fuel cell 1 and bidirectionally controls the output of the fuel cell 1. The first DC / DC converter 41 is connected to the storage battery 2 and secondly controls the charging / discharging thereof. DC / DC converter 42, the two DC / DC converters 41,
The output of 42 and the capacitor 3 are input, and the output is composed of a DC / AC inverter 43 connected to the power system 6 to supply power to the load device group 7. In the load device group 7, each load device has a data transmission device 71 that transmits measurement data of its own usage status and power consumption, and in the control device 5, the usage state of each load device in the load device group 7 or It has a data receiving device 51 for receiving the power consumption data. The power consumption can be measured by a current sensor, a power meter, or the like, and the data transmission / reception by the data transmission device 71 and the data reception device 51 can be realized by using a power line carrier, wireless, infrared rays, or the like. The control device 5 also has means for controlling the fuel cell 1 and the power conversion device 4.

Next, a control method of the power supply system according to the present invention will be described. The control device 5 monitors the usage state of each load device forming the load device group 7 via the data transmitting / receiving devices 51 and 71. Each load device of the load device group 7 is divided into two types, one for long time use and one for short time use, with respect to the average use time, with a specified time as a boundary. The time variation pattern determined by the ratio is also classified according to the magnitude of the power consumption variation. Here, the specified time is determined by the control response of the fuel cell 1 which is the power generation device.
For example, the time required to start the fuel cell 1 or the time required to stabilize when the amount of power generation is changed from 50% to 100% (rated) is the specified time. In addition, the minimum power consumption of the load devices used in the load device group 7 is used as a base component, and this power consumption peak is twice or more the base power or the power consumption is twice or more the base power amount. It is assumed that the device has a large fluctuation in power consumption.

FIG. 2 shows an example of the power consumption in the four types of load devices and the corresponding generated power and discharge power. Figure 2
When the load device as shown in (a) is used, its power consumption is made to correspond to the power generation amount of the power generation device. However, when a power generator having a slow response such as the fuel cell 1 is used as the power generator, the storage battery 2 is charged and discharged for the transient period until the start of power generation. When a load device such as that shown in FIG. 2B is used, in which the power consumption is almost constant but the usage time is short, the power consumption is made to correspond to the discharge of the storage battery 2. For a load device such as that shown in FIG. 2 (c) whose power consumption is pulse-like and peak-like, it is due to the discharge of the capacitor 3, but if it is not sufficient, power is supplied from the power system 6. Figure 2 (d) with large fluctuations in power consumption
For a load device such as the above, only the base portion of its power consumption is made to correspond to the fuel cell 1 and the storage battery 2 according to the average usage time of the load device used, and the remaining fluctuations are stored in the capacitor 3 or the power system 6. Power from.

In this way, by grasping the power consumption characteristics and the usage status of each load device constituting the load device group 7 in the control device 5, even if the power consumption increases, the increase is temporary or short. If so, it does not try to increase the amount of power generation, and thus the change in the amount of power generation in the fuel cell 1 can be minimized. This leads to the effects of improving the total efficiency and extending the life of the fuel cell system. Further, the control device 5 also grasps the remaining capacity of the storage battery 2 at the same time to increase the power generation amount of the fuel cell 1,
Alternatively, charging control is performed from the power system 6. For example, the battery may be charged when the remaining capacity of the storage battery 2 falls below a certain level, or at midnight when the load device is not often used. Alternatively, if the load device of the load device group 7 corresponding to the storage battery is controlled so as to be frequently charged when it is not used, the capacity of the storage battery 2 can be suppressed to a small value.

In the control example described above, it is assumed that the characteristics of each load device are known in advance, and the power consumption of the load device in use is allocated to the power generation device such as the fuel cell 1 and the storage battery 2 for control. . As a further control method, while measuring the power consumption of each load device, each load device is classified by use time based on the data of the use time and power consumption pattern, and the power consumption of each load device is analyzed and based on It is also possible to control while learning to decompose into minutes and peaks. That is, the power generation amount of the fuel cell 1 is controlled for the base portion of the load device used for a long time, and the charge / discharge amount of the storage battery 2 is controlled for the base portion of the load device used for a short time. However, short-term fluctuations in power consumption are dealt with by discharging a capacitor such as the capacitor 3 or the power system 6.

[0013]

As described above, according to the present invention,
As an operation method that minimizes the amount of power received from the power system by detecting the usage status of each load device or the power consumption of each, and controlling the amount of power generation and charging / discharging Can be suppressed to a minimum, and the load on the power supply system, particularly on the power generation device, can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a system configuration according to the present invention.

FIG. 2 is a power consumption variation diagram showing power consumption of the load device according to the present invention and power generation and discharge power corresponding thereto.

FIG. 3 is a block diagram showing a configuration of a conventional power supply system.

[Explanation of symbols]

1: Power generator (fuel cell) 2: Storage battery 3: Capacitor 4: Power converter 5: Control device 6: Power system 7: Load device group

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Satoshi Otsu             2-3-1, Otemachi, Chiyoda-ku, Tokyo             Inside Telegraph and Telephone Corporation (72) Inventor Mikio Yamazaki             2-3-1, Otemachi, Chiyoda-ku, Tokyo             Inside Telegraph and Telephone Corporation (72) Inventor Nobuhiko Yamashita             2-3-1, Otemachi, Chiyoda-ku, Tokyo             Inside Telegraph and Telephone Corporation (72) Inventor Kunitoshi Tazume             2-3-1, Otemachi, Chiyoda-ku, Tokyo             Inside Telegraph and Telephone Corporation (72) Inventor Yasushi Hiraoka             2-3-1, Otemachi, Chiyoda-ku, Tokyo             Inside Telegraph and Telephone Corporation F term (reference) 5G066 HB07 HB09 JA07 JB03 JB04

Claims (3)

[Claims] 1. A power supply system having a power generation device, a storage battery, a power storage device, a power conversion device, and a control device, the power supply system being connected to a power system and a plurality of load devices. The load device is a load device group having means for detecting information on its usage or power consumption and means for transmitting the detected information, and the control device has been transmitted from the load device group. And a means for receiving information on the state of use or power consumption, and means for controlling the power generation amount of the power generation device and the charge / discharge amount of the storage battery based on the received information, the power conversion device, A power conversion converter corresponding to each of the power generation device and the storage battery, an inverter for supplying power to the plurality of load devices, and pulse-shaped peak load power fluctuation Power supply system, characterized by comprising a terminal connected to the capacitor or power system because. 2. The control method for a power supply system according to claim 1, wherein each load device is divided into two types according to a size with respect to a specified time determined by a control response of the power generator with respect to an average usage time, and consumption. Regarding the electric power, the ratio of the peak electric power consumption to the base electric power, which is the minimum electric power consumption, is divided into two types, that is, a predetermined ratio, that is, a large amount and a small amount, and each load connected to the power conversion device. Regarding the device, for the load device whose average usage time is the specified time or more and power consumption fluctuation is less than the specified ratio, the power generation amount of the power generation device is controlled, and power consumption fluctuation occurs when the average usage time is the specified time or less Controls the charge / discharge amount of the storage battery for load devices with the specified ratio or less, and discharges the capacitor for load devices with power consumption fluctuations of the specified ratio or more. Or a power supply system control method characterized by being supported by a power system. 3. The control method for a power supply system according to claim 1, wherein each load device is divided into two types according to a prescribed time determined by the response of the power generator with respect to an average usage time, and a power consumption pattern is determined. Decompose into a base component and a fluctuation component, and for each load device used, control the power generation amount of the power generator for the base component of the load device whose average usage time is the specified time or more However, the charging / discharging amount of the storage battery is controlled for the base portion of the load device having an average usage time of the specified time or less, and the storage battery is discharged or changed for the power consumption variation of the base portion or more. A control method for a power supply system, which is characterized by being supported by a power system.