JP2012190810A - Fuel cell system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell system in which the impact of harmonic output current distortion from an auxiliary machine on the commercial power supply side can be eliminated by changing over the auxiliary machine power supply from the commercial power supply to direct supply from fuel cells when power is generated by fuel cells.SOLUTION: The fuel cell system comprises: a fuel cell 11; DC/AC conversion means 12; operation control means 14 for controlling a series of operations from start-up to power generation; power supply changeover means 15 for changing over a power supply source to an auxiliary machine 17 between the fuel cell 11 and a commercial power supply; and auxiliary machine power supply generation means 16 for generating a power supply for the auxiliary machine based on the power from the fuel cell 11 or the commercial power supply. The operation control means 14 controls the power supply changeover means 15 to changeover the power supply source of the auxiliary machine power supply generation means 16 to power supply from the fuel cell 11 after power is generated by the fuel cell thus eliminating the impact of harmonic output current distortion from the auxiliary machine on the commercial power supply side thus performing stable power generation control when power is generated by the fuel cell.

Description

  The present invention relates to a fuel cell system that generates power using a fuel cell.

In the conventional fuel cell system, auxiliary power is supplied from a commercial AC power supply when the fuel cell is stopped, and the inverter output is soft-started after power generation starts, that is, fuel that gradually supplies power from the AC output power. There was a battery system. (For example, refer to Patent Document 1). FIG. 6 shows a conventional control device for a fuel cell system described in Patent Document 1. In FIG.

  In FIG. 6, the fuel cell 1 supplies fuel gas and oxidant gas to the fuel electrode and oxidant electrode, generates power using an electrochemical reaction, and extracts DC power from between the electrodes, and the output side cuts off the grid connection. The inverter 4 and the auxiliary device disconnection circuit breaker 5 are connected in series to the commercial AC power source 3, and the inverter 2 for converting the DC power output from the fuel cell 1 into alternating current, the grid interconnection circuit breaker 4 and the auxiliary circuit breaker 4 An auxiliary machine 6 connected to a connection point with the machine disconnection circuit breaker 5 and a control circuit 7 for controlling the output power of the inverter 2 are configured. When the fuel cell 1 is stopped, the auxiliary machine is disconnected. The circuit breaker 5 is closed and the grid interconnection circuit breaker 4 is opened to supply power from the commercial AC power source 3 to the auxiliary device 6. When the fuel cell 1 starts generating power, the control circuit 7 soft-starts the inverter voltage. When the inverter output voltage is established, Mitsururen system breaker 4 is closed, it has been supplied to the inverter output power to the auxiliary machine.

Japanese Patent Application Laid-Open No. 10-210685

  However, in the conventional configuration, auxiliary power is supplied from the commercial power source when the fuel cell is stopped, and from the inverter output during fuel cell power generation. In either case, power is supplied from the commercial power source side. Therefore, there is a problem that the influence of the harmonic output current distortion from the auxiliary machine is large.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and an object of the present invention is to suppress the occurrence of harmonic output current distortion from an auxiliary machine to the commercial power supply side and eliminate the influence during fuel cell power generation.

  In order to solve the above-described conventional problems, the fuel cell system of the present invention switches auxiliary power to supply from the fuel cell during fuel cell power generation.

  With this configuration, at the time of fuel cell power generation, it is possible to suppress the occurrence of harmonic output current distortion from the auxiliary machine to the commercial power supply side and to eliminate the influence.

  According to the fuel cell system of the present invention, at the time of fuel cell power generation, particularly at the rated power generation, it is possible to suppress the occurrence of the harmonic output current distortion from the auxiliary machine to the commercial power supply side and to eliminate the influence. In addition, when an abnormality occurs in the system, the fuel cell system can be safely stopped.

1 is a configuration diagram of a fuel cell system according to Embodiment 1 of the present invention. Configuration diagram of a fuel cell system according to Embodiment 2 of the present invention Configuration diagram of fuel cell system according to Embodiment 3 of the present invention Configuration diagram of fuel cell system according to Embodiment 4 of the present invention Configuration diagram of fuel cell system according to Embodiment 5 of the present invention Configuration diagram of conventional fuel cell system

The first invention is
A fuel cell;
DC / AC conversion means connected to a commercial power supply, converting DC power from the fuel cell to AC power, and supplying AC power to a household load together with the commercial power supply;
Operation control means for controlling a series of operations from startup to power generation;
Power supply switching means for switching the power supply source to the auxiliary machine between the fuel cell and the commercial power supply;
Auxiliary power generation means for generating the auxiliary power based on the power from the fuel cell or the commercial power supply,
Commercial power supply abnormality detection means for detecting a system abnormality in the commercial power supply,
In a fuel cell system comprising:
The operation control means supplies power from the commercial power source before power generation by the fuel cell to the power source of the auxiliary power generation means by the power switching means, and from the fuel cell after power generation by the fuel cell. When the commercial power supply abnormality detection means detects an abnormality in the commercial power supply, the power supply from the fuel cell to the auxiliary machine is continued after the output of the alternating current power by the direct current alternating current conversion means is stopped. Then, by performing the stop process of the fuel cell system by the auxiliary machine, it is possible to suppress the occurrence of harmonic output current distortion from the auxiliary machine to the commercial power source side and eliminate the influence at the time of fuel cell power generation. it can. In addition, even if some abnormality occurs in the commercial power supply and the power output from the DC / AC converter stops, the power supply is continuously supplied from the fuel cell to the auxiliary machine, and the process for completely stopping the fuel cell system is performed. It becomes possible to carry out sequentially.

  The second aspect of the invention is particularly provided with a direct current voltage detection means in addition to the fuel cell system of the first aspect of the invention, and the operation control means detects by the direct current voltage detection means that the direct current voltage at the fuel cell output is equal to or higher than a threshold value. In this case, the auxiliary power source is switched to the power supply from the fuel cell by the power switching means, so that the auxiliary power source is used after the DC voltage in the fuel cell rises to a stable voltage. It is possible to suppress deterioration of characteristics due to a sudden change in power.

  According to a third aspect of the invention, in particular, when the direct current voltage detection means detects that the direct current voltage at the fuel cell output is equal to or lower than the threshold, the operation control means of the second aspect of the invention controls the auxiliary power source as the power supply switching means. By switching to the power supply from the commercial power supply, the load on the fuel cell is reduced when the voltage drops during the power generation of the fuel cell, and the power is supplied at a more accurate timing when the power generation of the fuel cell is stopped. The source can be switched, and both can suppress the deterioration of the characteristics of the fuel cell.

  The fourth aspect of the invention further includes a current measuring means in addition to the fuel cell system of the first aspect of the invention, and the operation control means has a current equal to or greater than a certain current by the current measuring means when the auxiliary power is supplied from the fuel cell. By preventing the current from flowing into the auxiliary machine, it is possible to prevent an inrush current or an excessive current from flowing into the auxiliary machine, and to suppress the deterioration of the characteristics of the fuel cell.

In the fifth aspect of the invention, in particular, when the operation control means of the fourth aspect of the invention detects that a current of a certain current or more has flowed to the auxiliary equipment by the current measuring means when the auxiliary equipment power is supplied from the fuel cell, By switching the auxiliary power supply source from the commercial power supply by the power supply switching means, it is possible to suppress the characteristic deterioration due to the sudden change in the output current of the fuel cell.

  According to a sixth aspect of the invention, in particular, in addition to the fuel cell system of the first aspect, the operation control means is present in a path from a fuel processing device that processes fuel to the fuel cell in a stop process of the fuel cell system. By purging hydrogen, the fuel cell system is safely stopped.

  In addition to the fuel cell system of the first invention, the seventh invention is provided with an abnormality notification means, and the operation control means stops the AC power output by the DC / AC conversion means when the commercial power supply abnormality is detected by the commercial power supply abnormality detection means. After that, the power supply from the fuel cell is continued, the fuel cell system is stopped by the auxiliary machine, and the abnormality is notified by the abnormality notification means, so that the abnormality is notified after the fuel cell system is completely stopped. Therefore, it is possible to confirm the abnormality notification content with peace of mind.

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 is a configuration diagram of a fuel cell system according to Embodiment 1 of the present invention.

  In FIG. 1, power generation is performed in a fuel cell 11 using a fuel containing a hydrocarbon such as methane such as city gas as a raw material. The DC / AC converting means 12 is connected to a commercial power source, converts DC power from the fuel cell 11 into AC power, and supplies the AC power to the household load 13 together with the commercial power source. The operation control means 14 controls a series of operations from startup to power generation. The power switching means 15 switches the power supply source to the auxiliary machine 17 between the fuel cell and the commercial power source. A power supply for the auxiliary machine 17 is made by the auxiliary machine power generation means 16 based on the electric power from the switched fuel cell 11 or the commercial power supply.

  Here, examples of the auxiliary machine 17 include pumps such as a purified air pump, a reformed water pump, a metamorphic water pump, a purified water pump, and a cooling water pump, which control the operation amount by on / off control. . In addition, there are valves such as a proportional valve, a solenoid valve, and a mixing valve, and on / off control of fuel and air is performed. There are also fan motors such as a booster, a combustion fan, a cooling fan, and a ventilation fan, and the rotational speed is controlled.

  The operation control unit 14 supplies power from the commercial power source, that is, an AC power source, before power generation by the fuel cell 11 as a power source of the auxiliary power generation unit 16 by the power source switching unit 15. Is switched to direct power supply from the fuel cell 11, that is, a DC power source. After the power source is switched as described above, the auxiliary power source generating means 16 generates power to be supplied to the auxiliary device 17, that is, the auxiliary devices described above as an example.

  Here, the power generated by the auxiliary power generation means 16 is 24V DC for valves and pumps, 12V DC for fan motors, and 5V DC for a control circuit such as a microcomputer.

  That is, at the start-up before the power generation by the fuel cell 11, a power source of AC24V, DC24V, DC12V, DC5V is produced from the commercial power source AC100V. This is an AC-DC converter power supply. After the power generation by the fuel cell 11, the power source of the fuel cell 11 is made from about DC50V to DC24V, DC12V, DC5V. This is a DC-DC converter power source, and the power source is created only on the direct current side, and does not affect the commercial power source side at all.

According to such a configuration, during fuel cell power generation, the auxiliary power source is taken from the fuel cell side, that is, the DC power source side, and the generation of harmonic output current distortion from the auxiliary device to the commercial power source side is suppressed, The influence can be eliminated.

(Embodiment 2)
FIG. 2 is a configuration diagram of a fuel cell system according to Embodiment 2 of the present invention. In FIG. 2, the same components as those in FIG.

  In FIG. 2, the DC voltage detection means 18 is connected to the output terminal of the fuel cell 11 and directly detects the DC voltage output of the fuel cell 11.

  When the DC voltage detection means 18 detects that the DC voltage value at the output terminal of the fuel cell 11 is equal to or greater than a threshold value, in this case, DC 35V or more, the operation control means 14 switches the power source of the auxiliary power source. By means 15, the commercial power supply is switched to the DC power supply from the fuel cell 11.

  Here, the above-mentioned threshold value DC35V or more is a voltage on the DC input side capable of a rated output by the DC / AC conversion means 12, here 1kW output, and is a voltage at which stable fuel cell power generation can be continued if this voltage is exceeded. is there. Moreover, if it is DC35V or more, each power supply of voltage DC24V, DC12V, DC5V used in auxiliary machinery can be made with a DC-DC converter power supply.

  According to such a configuration, since the auxiliary power supply is used after the DC voltage in the fuel cell rises to a stable voltage, it is possible to suppress deterioration of characteristics due to a sudden change in the output power of the fuel cell.

  In addition, when the direct current voltage detection means 18 detects that the direct current voltage at the output of the fuel cell 11 is equal to or lower than the threshold value, the operation control means 14 selects the auxiliary power source from the commercial power supply by the power supply switching means 15. Switching to power supply.

  When it is detected that the DC voltage value at the output terminal of the fuel cell 11 is equal to or less than the threshold value, here, the operation control means 14 is DC 30 V or less, the operation control means 14 supplies the auxiliary power supply source by the power switching means 15. Is switched to AC power supply from commercial power.

  Here, the above-mentioned DC 30 V or lower is equal to or lower than the voltage required for boosting to DC 350 V by the DC-DC converter of the internal circuit in the DC-AC converter 12 and is a voltage at which AC 200 V output cannot be formed. Voltage. Also, at DC 30 V or less, among the voltages used in the auxiliary machinery, a DC 24 V power source cannot be formed by a DC-DC converter power source.

  According to such a configuration, at the time of a voltage drop during power generation of the fuel cell, the burden on the fuel cell is reduced, and when the power generation of the fuel cell is stopped, the power supply source can be switched at a more accurate timing, In any case, deterioration of the characteristics of the fuel cell can be suppressed.

(Embodiment 3)
FIG. 3 is a configuration diagram of a fuel cell system according to Embodiment 3 of the present invention. In FIG. 3, the same components as those in FIG. 1 or FIG.

  In FIG. 3, the direct current value flowing from the fuel cell 11 to the auxiliary machine 17, more precisely, the power supply switching means 15 is measured by the current measuring means 19.

When the auxiliary power supply is supplied from the fuel cell 11, the operation control unit 14 causes the current measuring unit 19 to pass a current that is equal to or greater than a predetermined current value, in this case, 1.5 times or more of the rated current, to the auxiliary unit 17. It is something to prevent.

  In other words, the operation control means 14 monitors how much inrush current flows at the moment when the auxiliary power source is switched from the commercial power source to the fuel cell 11, and by the current limiting resistor or the like (not shown), the fuel cell 11 This prevents excessive current from flowing during supply of direct current from

  According to such a configuration, it is possible to prevent an inrush current or an excessive current from flowing into the auxiliary machine, and it is possible to suppress deterioration in characteristics of the fuel cell.

  Further, when the auxiliary power supply is supplied from the fuel cell 11, the operation control means 14 determines the auxiliary power supply source when the current measuring means 19 detects that a current of a predetermined current value or more has flowed into the auxiliary equipment 17. The power source switching means 15 switches to power supply from a commercial power source.

  That is, the operation control means 14 detects that a current of a certain current value or more, in this case, a current of 1.5 times or more of the rated current, flows to the auxiliary device 17 when the auxiliary power is supplied from the fuel cell 11. In this case, if an excessive current more than the normal power generation current flowing in the DC / AC converting means 12 flows, there is a risk of deteriorating the characteristics of the fuel cell 11. In this case, the auxiliary power supply source is switched to the power switching means. 15, switching to power supply from a commercial power source and continuing stable power generation.

  According to this configuration, it is possible to suppress characteristic deterioration due to a sudden change in the output current of the fuel cell.

(Embodiment 4)
FIG. 4 is a configuration diagram of a fuel cell system according to Embodiment 4 of the present invention. In FIG. 4, the same components as those in FIG. 1, FIG. 2, and FIG.

  In FIG. 4, the commercial power supply abnormality detection means 20 detects various system abnormalities in the commercial power supply, for example, instantaneous power failure, instantaneous voltage drop, line overvoltage, overcurrent, voltage phase shift, and the like.

  When the commercial power supply abnormality is detected by the commercial power supply abnormality detection unit 20, the operation control unit 14 continues to supply power from the fuel cell 11 even after the AC power output is stopped by the DC / AC conversion unit 12, and the fuel cell system by the auxiliary machine 17 is operated. The stop process is performed.

  That is, the operation control means 14 stops the AC power output by the DC / AC conversion means 12 when the commercial power supply abnormality is detected, and continues to receive the direct DC power supply directly from the fuel cell 11 even after being disconnected from the commercial power supply. The fuel cell system is stopped by the auxiliary machine 17, for example, hydrogen existing in a path (not shown) from the fuel processing device to the fuel cell 11 is purged to safely stop the fuel cell system. The surplus DC power is processed in the fuel cell 11.

  According to such a configuration, even after an abnormality occurs in the commercial power supply and the power output from the DC / AC converter stops, the power is continuously supplied from the fuel cell to the auxiliary machine to completely stop the fuel cell system. Therefore, it is possible to sequentially perform the processing for the above.

Further, the operation control means 14 supplies power from the fuel cell 11 to the auxiliary machine 17 until commercial power abnormality is detected by the commercial power abnormality detection means 20 and until AC power output is resumed by the DC / AC conversion means 12 after a certain time. And the standby process of the fuel cell system by the auxiliary machine 17 is performed.

  In other words, the operation control means 14 is able to output the AC power by the DC / AC conversion means 12 within about 1 minute until the grid connection is resumed in the event of a commercial power supply abnormality that recovers in a short time such as an instantaneous power failure or line overvoltage. During this time, the power supply from the fuel cell 11 to the auxiliary machine 17 is continued, and standby processing of the fuel cell system by the auxiliary machine 17, for example, power in the fuel cell 11 is consumed or stored in the system path. Etc. are performed.

  According to such a configuration, after some abnormality occurs in the commercial power supply and the power output from the DC / AC converter is temporarily stopped, the power is continuously supplied from the fuel cell to the auxiliary machine until the output is restarted. The standby process can be safely performed by consuming electric power.

(Embodiment 5)
FIG. 5 is a configuration diagram of a fuel cell system according to Embodiment 5 of the present invention. 5, the same components as those in FIG. 1, FIG. 2, FIG. 3, and FIG.

  In FIG. 5, an abnormality notifying means 21 notifies an abnormality when the commercial power supply abnormality detecting means 20 detects that some abnormality has occurred in the commercial power supply. Anomaly is notified by notification (not shown) by chime, voice synthesis or the like.

  When the commercial power supply abnormality is detected by the commercial power supply abnormality detection unit 20, the operation control unit 14 continues to supply power from the fuel cell 11 even after the AC power output is stopped by the DC / AC conversion unit 12, and the fuel cell system by the auxiliary machine 17 is operated. After the stop process is performed, abnormality notification by the abnormality notification means 21 is performed.

  In other words, the operation control unit 14 detects an abnormality that does not return in a short time with a commercial power source or an abnormality that causes a failure of the DC / AC conversion unit 12 from the fuel cell 11 in order to safely stop the system. After the power supply is continued and the stop process of the fuel cell system by the auxiliary machine 17 is performed, the abnormality notification means 21 notifies the abnormality to the user or service person.

  According to this configuration, since the abnormality is notified after the fuel cell system is completely stopped, the abnormality notification content can be confirmed with peace of mind.

  In the fuel cell system of the present invention, during power generation by the fuel cell, since the auxiliary power source is directly taken from the fuel cell output, the generation of harmonic output current distortion from the auxiliary device to the commercial power source side can be suppressed, and the influence thereof can be reduced. This is useful for a fuel cell system in which stable power generation is performed using a fuel cell. This can also be applied to power generation systems using other types of batteries and power sources.

DESCRIPTION OF SYMBOLS 11 Fuel cell 12 DC-AC conversion means 13 Domestic load 14 Operation control means 15 Power supply switching means 16 Auxiliary power generation means 17 Auxiliary equipment 18 DC voltage detection means 19 Current measurement means 20 Commercial power supply abnormality detection means 21 Abnormality notification means 21

Claims (7)

A fuel cell;
DC / AC conversion means connected to a commercial power supply, converting DC power from the fuel cell to AC power, and supplying AC power to a household load together with the commercial power supply;
Operation control means for controlling a series of operations from startup to power generation;
Power supply switching means for switching the power supply source to the auxiliary machine between the fuel cell and the commercial power supply;
Auxiliary power generation means for generating the auxiliary power based on the power from the fuel cell or the commercial power supply,
Commercial power supply abnormality detection means for detecting a system abnormality in the commercial power supply,
In a fuel cell system comprising:
The operation control means supplies power from the commercial power source before power generation by the fuel cell to the power source of the auxiliary power generation means by the power switching means, and from the fuel cell after power generation by the fuel cell. When the commercial power supply abnormality detection means detects an abnormality in the commercial power supply, the power supply from the fuel cell to the auxiliary machine is continued after the output of the alternating current power by the direct current alternating current conversion means is stopped. Then, stop processing of the fuel cell system by the auxiliary machine,
A fuel cell system. DC voltage detection means for detecting a DC voltage at the output end of the fuel cell,
When the direct current voltage detection means detects that the direct current voltage at the output end of the fuel cell is equal to or higher than a threshold value, the operation control means causes the auxiliary power source to be connected to the fuel cell by the power supply switching means. 2. The fuel cell system according to claim 1, wherein the fuel cell system is switched to a power supply from the power source.   When the direct current voltage detection means detects that the direct current voltage at the output end of the fuel cell is equal to or lower than a threshold value, the operation control means causes the auxiliary power source to be connected to the commercial power supply by the power supply switching means. 3. The fuel cell system according to claim 2, wherein the fuel cell system is switched to a power supply from. A current measuring means for measuring a direct current value flowing from the fuel cell to the auxiliary machine,
2. The operation control means prevents the current measuring means from flowing a current of a predetermined current or more to the auxiliary machine when the auxiliary machine power is supplied from the fuel cell. Fuel cell system.   The operation control means, when the auxiliary power supply is supplied from the fuel cell, when the current measuring means detects that a current of a predetermined current or more has flowed to the auxiliary equipment, 5. The fuel cell system according to claim 4, wherein the power source switching means switches to power supply from the commercial power source. The operation control means purges hydrogen existing in a path from a fuel processing apparatus that processes fuel to the fuel cell in a stop process of the fuel cell system.
The fuel cell system according to claim 1. Provided with an abnormality notification means for notifying the abnormality content,
When the commercial power supply abnormality is detected by the commercial power supply abnormality detection means, the operation control means continues to supply power from the fuel cell even after the AC power output is stopped by the DC / AC conversion means, so that the fuel by the auxiliary machine is continued. 2. The fuel cell system according to claim 1, wherein after the stop processing of the battery system is performed, abnormality notification by the abnormality notification unit is performed.