JPH06295735A - Fuel cell power generation system - Google Patents

Abstract

PURPOSE:To continue operation of a fuel cell stably even if a power failure is caused in commercial electric power supply operated cooperatively with the fuel cell by arranging a means to switch electric power supply of an equipment for exhaust heat and ventilation from the commercial electric power supply to the fuel cell when the power failure is caused in the commercial electric power supply. CONSTITUTION:When voltage of commercial electric power supply 22 is lowered, the voltage drop is detected by a lacking voltage detector 15, and a signal is transmitted to a timer 16. When a voltage drop condition continues over prescribed time, respective switches 17-19 for a cooling water pump 11, a cooling tower 12 and a fan 13 are opened simultaneously by a signal from the timer 16. In succession, a double-throw switch 20 is switched to a contact point (b) (fuel cell 1 side) from a contact point (a) (commercial electric power supply 22 side) so far. Afterwards, the switches 17-19 are closed successively.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a fuel cell power generation system.

[0002]

2. Description of the Related Art A fuel cell, which uses oxygen and hydrogen as an oxidant and a fuel, directly converts the chemical energy originally possessed by the fuel into electric energy, has attracted attention from the viewpoint of resource saving, environmental protection, etc. Has been done.

In operating the fuel cell, it is necessary to operate auxiliary equipment such as a cooling water pump, an air blower, a fuel cell main body and a heater for heating the catalyst. A power supply is used. On the other hand, the temperature of a certain level or higher is required for the reaction of the fuel cell to proceed, but the amount of heat generated from the fuel cell increases as the reaction of the fuel cell becomes active. A system for cooling is also required. Therefore, it is necessary to stably operate the exhaust heat treatment equipment such as the cooling pump and the cooling tower and the ventilation equipment during the operation of the fuel cell. Usually, a commercial power supply is used for the operation of these equipment.

It is of course possible to operate the fuel cell independently, but it is often the case that the fuel cell is operated in connection with a commercial power source. FIG. 3 shows an electric circuit of a conventional fuel cell power generation system. Is an example. The direct current output from the fuel cell 1 is converted into alternating current by the inverter 4 via the inductance 2 and the capacitor 3, the voltage is adjusted to, for example, 200 V by the transformer 5, and the transformer externally provided from the output terminal A via the switch 6. It is boosted at 21. The output voltage of the fuel cell package 10 (enclosed by the broken line) is boosted by the transformer 21 to 6600 V, which is convenient for interconnection with the commercial power supply 22, for example.

The fuel package 10 is provided with various auxiliary machines 7. The auxiliary machine 7 is driven by a commercial power source 22 via a switch 8 when the fuel cell 1 is started, but the fuel cell 1 is in steady operation. After entering, it is driven by the output of the fuel cell 1.

On the other hand, in the exhaust heat treatment equipment such as the cooling pump (CP) 11 and the cooling tower (CT) 12 and the ventilation equipment in the fuel cell chamber such as the fan (F) 13, the output of the commercial power source 22 is converted to 200 V by the transformer 23, for example. The voltage is adjusted so that it is always driven.

The power supply of the exhaust heat treatment equipment and the ventilation equipment does not switch from the commercial power supply to the fuel cell on the way like the auxiliary equipment. This is because the rush current flows when the power source is switched, and is to prevent the rush current from adversely affecting the operation and load of the fuel cell. On the other hand, in the case of auxiliary equipment, VVVF (Variable Voltage) is used to control the rotation of the motor.
A device called Variable Frequency) is used, and this has the function of suppressing the rush current when the power source of the auxiliary equipment is switched from the commercial power source to the fuel cell, so that the adverse effect of the rush current can be avoided.

[0008]

The fuel cell is preferably operated stably at a constant temperature, and when the cell temperature rises too much, the fuel cell itself is subject to sintering of the catalyst, corrosion of cell constituents, decomposition and evaporation of electrolyte, and the like. Therefore, the operation is stopped when the temperature of the fuel cell becomes a certain temperature or higher. Therefore, in the fuel cell power generation system as shown in FIG. 3, when the power failure occurs, the power source of the equipment for recovering the exhaust heat of the fuel cell such as the cooling pump 11, the cooling tower 12 or the fan 13 disappears. The fuel cell cannot be cooled, and as a result, the temperature of the fuel cell rises, which may cause an emergency stop of the operation.
If the temperature of the fuel cell rises due to another cause other than a power failure and it is urgently stopped, the operation can be resumed by cooling the fuel cell with the exhaust heat treatment equipment, but during a power failure, the fuel cell body is left at a high temperature after an emergency stop. Therefore, there is a problem that the fuel cell deteriorates rapidly.

On the other hand, when a power failure occurs, it is possible to forcibly stop the operation of the fuel cell in order to prevent the above-mentioned temperature rise of the fuel cell, but the operation of the fuel cell is once stopped. Since it takes a certain amount of time to start up again, the operation must be stopped as much as possible.

The present invention has been made in view of the above points, and provides a fuel cell power generation system capable of stably continuing the operation of a fuel cell even if a commercial power supply operating in conjunction with the fuel cell fails. Especially.

[0011]

In order to achieve the above object, the present invention has a fuel cell package for converting the output of a fuel cell into an alternating current and outputs the same, for exhaust heat treatment and ventilation of the fuel cell. In the fuel cell power generation system in which the equipment is driven by a commercial power source, a switching means is provided for switching the power source of the equipment for exhaust heat and ventilation from the commercial power source to the fuel cell when the commercial power source fails.

[0012]

[Function] Since the power source of the equipment for exhaust heat and ventilation of the fuel cell is switched from the commercial power source to the fuel cell at the time of a power failure of the commercial power source, the exhaust heat and ventilation equipment can continue to operate, whereby the fuel cell Temperature rise can be avoided.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 1 is an electric circuit diagram of an embodiment of a fuel cell power generation system according to the present invention. In the figure, the same reference numerals as in FIG. 3 indicate the same components.

In the fuel cell package 10 of this embodiment,
In addition to the fuel cell 1, an inductance 2, a capacitor 3, an inverter 4, a transformer 5 and various auxiliary machines 7 are provided.

In this power generation system, the fuel cell 1
When starting, the auxiliary machine 7 is driven by the double throw switch 8
Is connected to the contact point a side by the commercial power source 22 via the output terminal A.

When the auxiliary device 7 is activated and the fuel cell 1 starts up and outputs the rated voltage, the double throw switch 8 is switched to the contact b side, and this time the auxiliary device 7 is driven by the output of the fuel cell 1. Driven.

The direct current output from the fuel cell 1 is converted into alternating current by the inverter 4 via the inductance 2 and the capacitor 3, the voltage is adjusted to, for example, 200 V by the transformer 5, and is externally provided from the output terminal A via the switch 6. Output to the transformer 21. The output voltage of the fuel cell package 10 is boosted by the transformer 21 to, for example, 6600 V, which is convenient for interconnection with the commercial power supply 22. The output from the fuel cell 1 can be output from the output terminal A ′ via the double throw switch 8 and the breaker 9.

On the other hand, the exhaust heat treatment equipment such as the cooling water pump (CP) 11 and the cooling tower (CT) 12 and the fan (F) 1
For example, ventilation equipment such as 3 is connected to the transformer 23 from the commercial power source 22 via the switches 17, 18 and 19, respectively, and is, for example,
The line is connected to a line for supplying an output whose voltage is adjusted to 0 V, and a double throw switch 20 is provided on the line so that it can be connected to the fuel cell output supply line from the output terminal A ′.

Further, an instrument transformer 14, an undervoltage detector 15 and a timer 16 are connected to the commercial power source 22 side of the double throw switch 20. Switches 17, 1
8, 19 and double throw switch 20 are timer 16
The output is used to open and close.

Next, the operation at the time of power failure in this embodiment will be described with reference to the flowchart of FIG.

When the voltage of the commercial power source 22 drops, the voltage drop is detected by the undervoltage detector 15 via the instrument transformer 14, and a signal is sent to the timer 16. However, since there may be a momentary power failure, the timer 16 measures the voltage drop duration time, and when the voltage drop state exceeds a predetermined time (for example, one minute), the timer 16 outputs the first and second switch open signals. Output sequentially.

The first switch open signal from the timer 16 first causes the switches 17, 18 and 19 to open. Then, for example, 1-2 seconds later, the double throw switch 20 is activated by the second switch open signal from the timer 16.
Is the contact point up to that point (the output supply line of the commercial power supply 22)
To contact b (the output supply line of the fuel cell 1). After that, first (for example, after 5 seconds) the switch 19
Are closed, then (eg, 30 seconds after switch 19 is closed) switch 18 and finally (eg, 30 seconds after switch 18 is closed) switch 17 is closed again. Switch 1 once like this
The reason for opening 7, 18, and 19 is to minimize the influence of load fluctuation when switching from the commercial power source to the fuel cell.

When the power failure of the commercial power source 22 is recovered, the double throw switch 20 may be manually switched to the a side.

[0025]

As described above, according to the present invention,
Even during a power failure of the commercial power source, the operation of the fuel cell can be stably continued without causing an emergency stop of the operation of the fuel cell or deterioration of the fuel cell.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram of an embodiment of a fuel cell power generation system according to the present invention.

FIG. 2 is a flowchart of an operation during a power failure according to the present invention.

FIG. 3 is an electric circuit diagram of an example of a conventional fuel cell power generation system.

[Explanation of symbols]

 1 Fuel Cell 2 Inductance 3 Capacitor 4 Inverter 5 Transformer 6 Switch 7 Auxiliary Equipment 8 Double Throw Switch 9 Breaker 10 Fuel Cell Package 11 Cooling Water Pump 12 Cooling Tower 13 Fan 14 Instrument Transformer 15 Undervoltage Detector 16 Timer 17 , 18, 19 Switch 20 Double throw switch 21 Transformer 22 Commercial power supply 23 Transformer

Claims (3)

[Claims] 1. A fuel cell power generation system having a fuel cell package for converting the output of a fuel cell into an alternating current to output the power, and a facility for exhaust heat treatment and ventilation of the fuel cell driven by a commercial power source A fuel cell power generation system characterized by further comprising switching means for switching the power source of the equipment for exhaust heat and ventilation from a commercial power source to a fuel cell. 2. The switching means comprises a power failure detecting means for detecting a power failure due to a voltage drop of a commercial power source, and a switch for switching based on an output of the power failure detecting means.
The fuel cell power generation system described in 1. 3. The fuel cell power generation system according to claim 2, wherein the power failure detection means outputs when the voltage drop state of the commercial power source continues for a predetermined time or longer.