JP2002315197A - Hybrid power supply system and its operation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hybrid power supply system for complexedly utilizing power supplied from an AC power supply such as a commercial power supply and at the same time effectively utilizing DC power that is supplied from a generation system or the like for utilizing natural energy, and to provide the operation method of the system. SOLUTION: The hybrid power supply system comprises an AC power supply line 4 for supplying AC power from an AC power supply 2 to an AC load 6, and DC power supply lines 21, 23, and 25 for supplying DC power to a DC load 12 from DC power supplies 8 and 10. The system also has a system connection inverter 16 and an AC/DC converter 14. When the supply voltage of the DC power supplies 8 and 10 is equal to or more than a first value, a system connection inverter 16 is driven and AC power is supplied to the AC power supply line 4. When the supply voltage is equal to or less than a specific, second value, a switch MC2 is closed, and power is supplied from the AC power supply line 4 to the DC load 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a hybrid power supply system capable of efficiently supplying power supplied from an AC power supply and a DC power supply to an AC load and a DC load, and a method of operating the hybrid power supply system.

[0002]

2. Description of the Related Art In recent years, there has been a growing demand for new energy due to the increasing awareness of environmental protection and the depletion of petroleum energy. Under such circumstances, various power generation systems utilizing natural energy such as a solar power generation system and a wind power generation system have appeared. Power generation systems that use these natural energies generate energy using the energy that exists in the natural world, such as sunlight and natural wind, so they are extremely clean without any adverse effects on the natural environment. Have a point. Expectations for future research and development are increasing.

On the other hand, recently, fuel cells that generate electricity by using various kinds of fuels for the purpose of preventing global warming and the like have attracted attention, and are expected to serve as a clean energy source for the environment in the future.

[0004] Such power generation systems and fuel cells utilizing natural energy are generally called distributed power sources. In most cases, the distributed power source generates DC power from its principle. On the other hand, the power generally supplied to homes, office buildings, factories, etc. is all AC power, and converted to AC power to supply the power generated using such natural energy. I needed to.

[0005]

However, loads that use electric power in homes, office buildings, factories, and the like, include:
There are also DC loads that run on DC power. Such a DC load converts the supplied AC power into DC power using an AC / DC converter and uses it. If the generated DC power is converted into AC power and supplied to such a DC load, the power loss due to the conversion is large and the efficiency is very low. Despite being produced using natural energy, it is not fully utilized, contrary to the purpose of using energy effectively.

There is a reason that power generated by using natural energy cannot be supplied to such a DC load. That is, in the case of a power generation system using natural energy, it is difficult to supply power stably because the power obtained depends on the weather conditions of the day. It is extremely difficult to supply power to a DC load using only a power generation system that uses natural energy. On the other hand, a power generation system that uses natural energy may generate excessive power, and in such a case, the excess generated power will be left over, and the generated power cannot be used effectively. , It may be wasted. For these reasons, a system that can efficiently operate a power generation system using natural energy has been desired.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and has as its object to provide a power generation system and the like utilizing natural energy while using power supplied from an AC power supply such as a commercial power supply in a combined manner. It is an object of the present invention to provide a hybrid power supply system and a method of operating the hybrid power supply system that can effectively use DC power supplied from a distributed power supply.

[0008]

In order to achieve the above object, a hybrid power supply system according to the present invention provides an AC power supply line for supplying AC power from an AC power supply such as a commercial power supply to an AC load. A DC power supply line for supplying DC power from a DC power supply to a DC load; AC / DC for obtaining AC power from the AC power supply line, converting the AC power into DC power, and supplying the DC power to the DC power supply line
A converter and a system interconnection inverter that detects a phase of the AC power supplied through the AC power supply line, converts DC power from the DC power supply into AC power according to the phase, and supplies the AC power to the AC power supply line. And a control means for controlling the drive of the grid-connected inverter and the AC / DC converter, wherein the control means receives a detection result from the status detection means. When it is determined that the supply power of the DC power supply exceeds the required power for the DC load, the grid-connected inverter is driven, and the DC load is supplied from the DC power supply based on the detection result from the status detection means. And driving the AC / DC converter when it is determined that power supply to the AC / DC converter is insufficient. (Claim 1).

In the method for operating a hybrid power supply system according to the present invention, AC power from an AC power supply such as a commercial power supply is supplied to an AC load via an AC power supply line, and the AC power is supplied via the DC power supply line. The DC power from the DC power supply is supplied to the DC load, and the power supply status of the DC power supply is detected by the status detection means. Based on the detection result from the status detection means, the power supply of the DC power supply is necessary for the DC load. When it is determined that the power exceeds the power, the phase of the AC power supplied to the AC power supply line is detected by driving the grid interconnection inverter, and the DC power from the DC power supply is converted into AC power according to the phase. Supply to the AC power supply line, and power supply from the DC power supply to the DC load is insufficient based on the detection result from the situation detection means. The, AC / DC when it is determined that that
AC power is obtained from the AC power supply line by driving a converter, converted into DC power, and supplied to the DC power supply line (claim 7).

In such a power supply system and its operation method, the DC power supplied from the DC power supply can be supplied to the DC load as it is, so that power loss due to conversion can be eliminated. Also, since the power supply status of DC power is detected, when the power supply of DC power is insufficient, the power supply of AC power can be automatically supplied to the DC load. When there is a margin, the surplus power can be converted into AC power and supplied to an AC load, and the power can be operated very efficiently.

In this power supply system, a distributed power supply is provided as a DC power supply. Examples of the distributed power source include a power generation device using natural energy such as a solar power generation device and a fuel cell. By using such a power source, clean energy having no adverse effect on the environment can be used, which can be used for energy saving.

In this power supply system, a power storage battery is provided as a DC power supply for acquiring and storing AC power from the AC power supply line at night (claim 3). With such a power storage battery, power supplied at night through the AC power supply line can be stored and used during daytime when power demand is high, and power costs can be reduced. Furthermore, if both the distributed power source and the power storage battery are provided, even if the power supply from the distributed power source is unstable, DC power can be supplied from the power storage battery that can supply power stably, and the DC load can be increased. , A stable power supply can be performed.

In this power supply system, a redox flow battery is provided as a power storage battery (claim 4). A redox flow battery can efficiently store a large amount of power and can sufficiently cope with daytime when demand is high.

The power supply system further comprises means for storing DC power supplied from the distributed power supply in the power storage battery (claim 5). By providing such a means, when there is room for the power supplied from the distributed power source such as a solar power generation device, the power can be stored in the power storage battery, and the power can be effectively used.

The power supply system has a function of detecting whether or not power is supplied to the AC power supply line, and has a function of securing emergency backup power to the power storage battery. The emergency backup power of the power storage battery is supplied to the DC load when the detecting means detects the power supply stop (claim 6). By providing such a function, it is possible to temporarily supply power to a load that must be operated even in an emergency such as a power outage or an emergency such as an emergency light or various security lightings. .

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a hybrid power supply system according to the present invention and an operation method thereof will be described below with reference to the accompanying drawings. 1 to 4 show an embodiment of a hybrid power supply system according to the present invention.

As shown in FIG. 1, this hybrid power supply system efficiently converts power supplied from AC power supply 2 and DC power supplies 8 and 10 into AC load 6 and DC load 12
System for supplying to The AC power supply 2 is a commercial power supply or the like that is generally supplied as power to each home or office building. The AC power supplied from the AC power supply 2 includes not only single-phase AC power supplied to general households but also three-phase AC power supplied to general industries such as factories. On the other hand, the DC power supplies 8 and 10 store electric power supplied from commercial power supplies and the like at night, including various types of distributed power supplies including power generation apparatuses utilizing natural energy such as solar power generation apparatuses and wind power generation apparatuses, and fuel cells. There is a power storage battery or the like for the purpose of eliminating the difference in power demand between day and night, which is supplied during the daytime when demand is high. In the present embodiment, a power storage battery 8 and a solar power generation device 10 are provided as DC power supplies.

The AC load 6 includes various electric devices such as an air conditioner installed in a building, and household appliances generally operated by AC power. In addition, the DC load 12
There are various DC-operated electrical devices including Hf lighting devices installed in buildings. The DC load 12 also includes an uninterruptible load 12b, such as an emergency light or various security lights that need to supply power in an emergency such as a power outage.

The configuration of the hybrid power supply system according to the present embodiment will be described in detail. This system is a system installed on an AC power supply line 4 connecting an AC power supply 2 and an AC load 6, as shown in FIG. The system includes an AC / DC converter 14 that acquires AC power from the AC power supply line 4 and converts the AC power into DC power.
Power storage battery 8 as a DC power supply and solar power generation device 1
And a system interconnection inverter 16 for converting DC power from 0 to AC power.

The AC / DC converter 14 is composed of a rectifying bridge circuit composed of a diode, a smoothing capacitor, etc., and converts the generated DC power into a DC / DC converter 18.
To the DC load via

On the other hand, the system interconnection inverter 16 detects the phase of the AC power supplied to the AC power supply line 4, generates AC power having an AC waveform matching the phase of the AC power, and generates the AC power. Output to the supply line 4. Then, the generated AC power is supplied to the AC load 6 through the AC power supply line 4.

In the present embodiment, the AC / DC converter 14 and the system interconnection inverter 16 are connected to the AC power supply line 4 by a common line 19. An insulation transformer (voltage ratio 1: 1) 20 for insulating the AC / DC converter 14 and the system interconnection inverter 16 from the AC power supply line 4 is provided on the line 19, A current breaker MCB1 also serving as short-circuit protection is provided.

The power storage battery 8 and the photovoltaic power generator 10 are connected to the system interconnection inverter 16 as DC power supplies. The power storage battery 8 and the photovoltaic power generator 10 are connected to the grid-connected inverter 16 by separate lines 21, respectively.
23.

Here, the solar power generation device 10 is installed as a so-called distributed power source in a factory, a building, a general house, or the like, on a rooftop or the like in a sunny place. DC power is generated according to the amount of solar radiation on that day.

On the other hand, the power storage battery 8 converts AC power from the AC power supply line 4 into electrochemical energy and stores it. The power storage battery 8 includes an AC / DC converter 22 between the power storage battery 8 and the AC power supply line 4, and converts AC power from the AC power supply line 4 into DC power before storing. The power storage battery 8 has two modes, a charging mode and a discharging mode.
The charging mode is set at night, and the AC power supplied at night is acquired and stored. Switching to the discharge mode during the daytime when demand is high, it plays the role of supplying power stored at night to greatly reduce power costs. Power storage battery 8
May be able to perform only one of charging and discharging, or may be capable of simultaneously performing charging and discharging.

In this embodiment, a redox flow battery is provided as the power storage battery 8. This redox flow battery is performed by circulating (Flow) a substance that causes a reduction / oxidation (Oxidation) reaction. It has the advantages of being simple, having a long service life, and having little standby loss and quick start-up. For example, there is an electrolyte using a vanadium ion aqueous solution as an electrolyte, and electric power can be efficiently stored. Since such a power storage battery requires a huge tank to store the electrolyte, it is installed in an extra space such as a pit space in a building.

Photovoltaic power generator 10 and power storage battery 8
2 connecting the power supply and the grid interconnection inverter 16
Current breakers MCB2 and MCB3, which also serve as overload and short-circuit protection, are provided on 1 and 23, respectively.
Further, a protection diode D for preventing backflow is provided on a line 23 connecting the photovoltaic power generator 10 and the grid interconnection inverter 16.
1 is interposed.

A branch line 25 extending to the DC / DC converter 18 is provided before the lines 21 and 23 are input to the system interconnection inverter 16.
The branch line 25 functions as a DC power supply line that directly supplies DC power supplied from the power storage battery 8 and the solar power generation device 10 to the DC load 12 via the DC / DC converter 18.

The DC / DC converter 18 stably supplies DC power supplied from the power storage battery 8 or the solar power generation device 10 or DC power generated by the AC / DC converter 14 to a DC load at an appropriate voltage. Play a role.

In the present embodiment, in order to detect the state of power supply from the power storage battery 8 or the photovoltaic power generation device 10, the voltage detector ( (Not shown). This voltage detector includes a power storage battery 8 and a solar power generation device 10.
Is to detect the supply voltage. The detected voltage increases and decreases according to the amount of power supplied from the power storage battery and the solar power generation device. Here, the drive of the system interconnection inverter and the AC / DC converter is controlled in accordance with the detection result of the voltage detector. That is, when the supply voltage of the power storage battery 8 and the photovoltaic power generator 10 is high, it is determined that there is surplus power, and the grid-connected inverter 16 is driven to use the surplus power as AC power to the AC power supply line 4. Supply.

On the other hand, when the supply voltage of the power storage battery 8 and the photovoltaic power generator 10 is low, it is determined that the power supply to the DC load 12 is insufficient, and the AC / DC converter 14 is driven to drive the AC power supply. DC load 12 from line 4
Power is supplied to. Here, when the supply voltage of the power storage battery 8 or the photovoltaic power generator 10 reaches or exceeds a predetermined first voltage value (here, DC345V), the power supplied to the power storage battery 8 or the photovoltaic power generator 10 is reduced. The power is supplied to the AC power supply line 4, and when the supply voltage of the power storage battery 8 or the solar power generation device 10 falls below a predetermined second voltage value (here, 300 V DC), the supply power of the AC power supply line 4 is changed to DC. Supply to load 12. In addition, AC /
The DC converter 14 is driven by the AC / DC converter 1
This is performed by closing a switch MC2 provided on the line 27 between the DC / DC converter 4 and the DC / DC converter 18.
At this time, the switch MC1 provided on the line 25 connecting the power storage battery 8 and the photovoltaic power generator 10 to the DC / DC converter 18 is opened, and the DC load from the power storage battery 8 and the photovoltaic power generator 10 is reduced. The power supply to 12 is shut off.

When the supply voltage from the power storage battery 8 or the solar power generation device 10 is between a predetermined first voltage value and a predetermined second voltage value, that is, within a range of 300 V to 345 V, the power storage battery 8 or the power supplied from the photovoltaic power generator 10 is directly supplied to only the DC load 12.

The switches MC1 and MC2 and the drive of the system interconnection inverter 16 are executed by a control unit (not shown) constituted by a computer or the like, and the detection result of the voltage detector is transmitted to this control unit. You. These controls are performed according to a program installed in the control unit.

As described above, by controlling the drive of the system interconnection inverter 16 and the AC / DC converter 14 according to the supply voltage from the power storage battery 8 or the solar power generation device 10, the power storage battery 8 or the solar power generation When the power supplied from the device 10 has a margin, the power can be automatically supplied to the AC power supply line 4, and the power supplied from the power storage battery 8 or the solar power generation device 10 to the DC load 12 is not sufficient. If it is sufficient, it is possible to automatically supply insufficient power to the DC load 12. by this,
The DC power from the DC power supply can be supplied to the DC load 12 as it is, and there is no power loss due to conversion as in the related art, and when the power is insufficient, the DC power is supplied from the AC power supply 2. And stable power supply can be performed. Further, the power supplied from the power storage battery 8 or the solar power generation device 10 can be efficiently used without waste.

Further, this system includes a line 29 for storing the power generated by the photovoltaic power generator 10 in the power storage battery 8 when the power supplied from the photovoltaic power generator 10 has a margin. This line 29 is provided with a switch MC5 and a diode D2 for preventing backflow. The opening and closing operation of the switch MC5 is performed by the above-described control unit. Receiving power from the photovoltaic power generator 10 and storing it in the power storage battery 8 is mainly performed when there is no DC load 12 or when the load is light. When the power supply line from the photovoltaic power generator 10 to the power storage battery 8 is provided, the photovoltaic power generator 8 and the DC load 12
A line between the DC load 12 and the grid-connected inverter 16 may be omitted, and only the power storage battery 8 may be connected to the DC load 12 and the grid-connected inverter 16.

Further, in this system, the power storage battery 8 has a function of securing emergency backup power. The emergency backup function is a function of assigning a part of the total capacity of the power storage battery to the emergency backup capacity and always ensuring power for this capacity. That is, when the total capacity of the power storage battery 8 is set to 100 and the emergency backup capacity is set to 20, the power storage battery 8 is always set to 0 during normal times other than an emergency.
The power is supplied between ~ 80 and the remaining 20 capacities are always left. Therefore, in an emergency,
The remaining 20 capacities can be reliably supplied as emergency backup power.

The AC power supply line 4 is provided with detection means such as a voltmeter as means for detecting whether or not power is being supplied. When the detecting means detects the stop of the power supply, the power storage battery 8 closes the switch MC1,
Electric power is supplied to the DC load 12. At this time, on the DC load 12 side, the uninterruptible load 12b and the normal load 12 that must be operated in an emergency including an emergency light, various security lights, and the like.
a, and if they are connected to separate lines 31 and 33 so as to be energized by separate switches MC3 and MC4, a very uninterruptible load 1
Power can be supplied only to the uninterruptible load 12b for a long time without waste.

Current breakers MCB1, MCB2, MCB
3. Switches MC1, MC2, MC3, MC4, MC
5, the AC / DC converter 14, the transformer 20, the system interconnection inverter 16, the DC-DC converter 18, and the diodes D1 and D2 are all housed and integrated in one device.

<< Daytime Operation Status >> The daytime operation status of this hybrid power supply system will be described. FIG.
Fig. 3 shows a daytime operation state of the hybrid power supply system according to the present embodiment. In the daytime, solar power generator 1
0, and the DC power from the photovoltaic power generator 10 and the power storage battery 8 is directly supplied to the DC load 12 as it is to supply the power stored by the power storage battery 8 at night. Is done. If the power supplied from the photovoltaic power generator 10 and the power storage battery 8 has a sufficient margin, the grid-connected inverter 16
Is driven to convert excess DC power into AC power, output the AC power supply line 4, and supply the AC load 6. Further, when there is enough power generated by the solar power generation device 10, the switch MC5 is closed and the power is stored in the power storage battery 8 via the line 29.

On the other hand, when the weather is bad and so much sunlight cannot be obtained, or when the power stored in the power storage battery 8 runs out, that is, when the supply voltage of this embodiment becomes 300 V or less, , Switch MC2 is closed and AC / DC
The AC power of the AC power supply line 4 is converted into DC power through the converter 14 and supplied to the DC load 12.

<< Night Operation Status >> Next, the night operation status of the hybrid power supply system will be described. FIG.
5 shows the nighttime operation status of the hybrid power supply system according to the present embodiment. At night, sufficient sunlight cannot be obtained, and there is no power supply from the solar power generation device 10. Also, the power storage battery 8 converts AC power supplied through the AC power supply line 4 into DC power and stores the DC power. Regarding the power supply to the DC load 12, the AC power from the AC power supply line 4 is converted into an AC / DC converter 14.
It converts it into DC power and supplies it.

<< Operational Status at the Time of Power Outage >> Next, an operational status when the power supply from the AC power supply is stopped will be described. FIG. 4 shows an operation state of the hybrid power supply system according to the present embodiment at the time of a power failure. When the detecting means provided on the AC power supply line 4 detects a power failure, the power storage battery 8 switches to the emergency backup mode, the switches MC1 and MC4 are turned on, and the emergency backup power of the power storage battery 8 is changed to an emergency light. It is supplied to the uninterruptible load 12b including various security lightings. The power storage battery 8 functions so as not to supply emergency backup power during normal times other than during an emergency.

<< Other Embodiments >> In this embodiment, as a means for detecting the power supply status of a DC power supply, that is, a photovoltaic power generator or a power storage battery, a voltage detector for detecting these supply voltages is provided. Although the system interconnection inverter and the AC / DC converter are controlled according to the supply voltage, the present invention is not limited to such means, and detects the power supply status of the photovoltaic power generator or the power storage battery. If it is a means, it may be equipped with a means to measure another element, and it may be a system that makes a judgment not only based on one measurement result but also based on more than one factor .

In the present invention, in addition to a redox flow battery as a power storage battery, for example, sodium-
A sulfur battery or the like may be provided.

[0045]

According to the hybrid power supply system and the method for operating the same according to the present invention, the DC power supplied from the DC power supply can be supplied to the DC load as it is, so that the power loss due to conversion can be eliminated. . Also, since the power supply status of the DC power is detected, when the power supply of the DC power supply is insufficient, the power supply of the AC power supply (commercial power supply) can be automatically supplied to the DC load. When the power supplied from the power supply has a margin, the surplus power can be converted into AC power and supplied to an AC load, and the power can be operated very efficiently (claims 1 and 7).

Further, by providing a distributed power supply as a DC power supply, a power generation apparatus using natural energy such as a solar power generation apparatus or a wind power generation apparatus, or a fuel cell, etc., can provide clean energy having no adverse effect on the environment. It can be used for energy saving (claim 2).

In addition, since a power storage battery is provided as a DC power supply for acquiring and storing AC power to be supplied at night and storing the power, the power supplied at night through the AC power supply line is stored and the power demand is high. Can be used during the day,
The power cost can be reduced (claim 3). Furthermore, if both the distributed power source and the power storage battery are provided, even if the power supply of the distributed power source is unstable, DC power can be supplied from the power storage battery that can supply power stably, and the DC load can be supplied to the DC load. On the other hand, stable power supply can be performed.

Further, by providing a redox flow battery as the power storage battery, a large amount of power can be efficiently stored, and it is possible to sufficiently cope with daytime when demand is high.

[0049] Further, by providing means for storing the DC power supplied from the distributed power supply in the power storage battery, if there is room for the power supplied from the distributed power supply, this is stored in the power storage battery. And can be used effectively (claim 5).

In addition, a detecting means for detecting whether or not power is supplied to the AC power supply line is provided, and the power storage battery is provided with a function of securing emergency backup power. By detecting the stoppage, the emergency backup power of the power storage battery is supplied to the DC load, so that it must be operated even in an emergency such as a power outage, for example, in an emergency such as an emergency light or various security lighting. Electric power can be temporarily supplied even to a load that is not required (claim 6).

[Brief description of the drawings]

FIG. 1 is a block circuit diagram showing a configuration example of a hybrid power supply system according to the present invention.

FIG. 2 is an explanatory diagram illustrating a nighttime operation state of the hybrid power supply system illustrated in FIG. 1;

FIG. 3 is an explanatory diagram illustrating a daytime operation state of the hybrid power supply system shown in FIG. 1;

FIG. 4 is an explanatory diagram illustrating an operation state of the hybrid power supply system illustrated in FIG. 1 at the time of a power failure.

[Explanation of symbols]

 2 AC power supply 4 AC power supply line 6 AC load 8 Power storage battery 10 Photovoltaic power generator 12 DC load 14 AC / DC converter 16 Grid-connected inverter 18 DC / DC converter

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hisao Noda 2- 15-2 Konan, Minato-ku, Tokyo Obayashi Gumi Tokyo Head Office (72) Inventor Takashi Abe 2- 15-2 Konan, Minato-ku, Tokyo Stock Company Obayashi Gumi Tokyo headquarters (72) Inventor Naoyoshi Tsutsui 2-15-2 Konan, Minato-ku, Tokyo Obayashi Gumi Tokyo headquarters F-term (reference) 5G066 HA06 HB06 HB09 JA07 JB03

Claims (7)

[Claims] An AC power supply line for supplying AC power from an AC power supply such as a commercial power supply to an AC load; a DC power supply line for supplying DC power from a DC power supply to a DC load; AC power supplied from the AC / DC converter and converted into DC power to be supplied to the DC power supply line.
A DC converter, and a grid-connected inverter that detects a phase of the AC power supplied through the AC power supply line, converts DC power from the DC power supply into AC power according to the phase, and supplies the AC power to the AC power supply line And a condition detecting means for detecting a power supply condition of the DC power supply; and a control means for controlling the drive of the system interconnection inverter and the AC / DC converter, wherein the control means detects a detection result from the condition detecting means. When it is determined that the power supplied from the DC power supply exceeds the required power for the DC load, the system interconnection inverter is driven, and the DC power is supplied from the DC power supply based on the detection result from the status detection means. When it is determined that the power supply to the load is insufficient, the AC / DC
A hybrid power supply system characterized by driving a converter. 2. The hybrid power supply system according to claim 1, wherein a distributed power supply is provided as said DC power supply. 3. The hybrid power supply system according to claim 1, further comprising a power storage battery for acquiring and storing AC power from the AC power supply line at night as the DC power supply. 4. The hybrid power supply system according to claim 3, further comprising a redox flow battery as the power storage battery. 5. The hybrid power supply system according to claim 3, further comprising means for storing DC power supplied from said distributed power supply in said power storage battery. 6. A power supply system comprising: a detection unit for detecting whether or not power is supplied to the AC power supply line; and a function of securing an emergency backup power to the power storage battery. The emergency backup power of the power storage battery is supplied to a DC load when a stop is detected.
6. The hybrid power supply system according to any one of 5. 7. An AC power supply from an AC power supply such as a commercial power supply is supplied to an AC load via an AC power supply line, and a DC power from the DC power supply is supplied to the DC load via a DC power supply line. When the power supply status of the DC power supply is detected by the status detection means, and when it is determined based on the detection result from the status detection means that the power supply of the DC power supply exceeds the required power for the DC load, a grid-connected inverter To detect the phase of the AC power supplied to the AC power supply line, convert the DC power from the DC power supply into AC power according to this phase and supply the AC power to the AC power supply line, When it is determined based on the detection result from the means that the power supply from the DC power supply to the DC load is insufficient, the AC / DC converter is driven to The method of operating a hybrid power supply system and supplying the AC power supply line the DC power supply line into a DC power to obtain the AC power from.