JP2002329518A - Fuel cell power generating system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell power generating system providing an operation of maximally maintaining an electric power utilization factor by surely preventing a reverse flow of electric power. SOLUTION: The fuel cell power generating system is used with a so-called power purchase system feeding power from an electric power system 23 to a load system 22 in addition to electricity fed from a fuel cell facility 24 via a main circuit 29a. In a fuel cell power generating facility provided with an auxiliary machine system 21 using heat generated from the fuel cell facility and a controller 25 controlling the fuel cell facility, the auxiliary machine system and the load system, the controller is provided with a means of taking in a received power value fed to the load system from the electric power system, an auxiliary machine power regulating system controlling the auxiliary machine system on the basis of the received power value taken in from the electric power system, a load regulating system controlling the load system, and a generating-end output regulating system controlling a generating-end output of the fuel cell facility. The reverse flow of electric power can be prevented even during power consumption deterioration of the load system 220.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell power generation system, and more particularly, to a fuel cell power generation system that reliably prevents reverse flow of electric power when applied for home use.

[0002]

2. Description of the Related Art Conventionally, a fuel cell is well known as a system for directly converting chemical energy of fuel into electricity.

[0003] In this fuel cell, electricity is directly extracted by electrochemically reacting hydrogen as a fuel with oxygen as an oxidizing agent. At the same time, electric energy can be extracted with high efficiency. It is a system that is quiet and does not emit harmful exhaust gas and has excellent environmental characteristics.

[0004] By the way, conventional fuel cells are usually premised on the management by the chief electrician technician, and therefore require some knowledge in operation.
In addition, the scale is several tens of kilowatts or more, which is medium or larger, and is often introduced into factories and used.

[0005] However, recently, when regulations have been deregulated, the development of small fuel cells has become active, and the spread of fuel cells for home use has been approaching. There is something to show.

A home fuel cell power generation system includes a fuel cell power generation plant system 1, an auxiliary system 2 as ancillary equipment,
Household load system 3 consuming household electricity, and power system 4
It is provided with.

[0007] The fuel cell power plant system 1 includes a fuel cell facility 5 and a control device 6.

The fuel cell equipment 5 includes a fuel processing system 7 such as a reformer, a fuel cell main body 8, an inverter 9, and a circuit breaker 10, and reforms the fuel supplied to the fuel processing system 7 to hydrogen. The reformed hydrogen is subjected to a chemical reaction by adding oxygen in the fuel cell body 8, and electricity generated at that time is converted into AC by an inverter 9, and the converted AC is turned into a circuit breaker 10.
Power is supplied to the household load system 3 via the main circuit line 11.

The control device 6 has a configuration in which a so-called fixed control circuit for issuing only an output command according to a schedule is incorporated in each of the auxiliary system 2, the fuel cell system 5, and the household load system 3, for example. ing.

On the other hand, the auxiliary system 2 includes a pump 12 and a hot water storage tank 1.
3, a heat exchanger 14 and a pump 12
While being circulated through the heat exchanger 14, the heat is heated by the heat from the fuel processing system 7 of the fuel cell equipment 5 and the fuel cell main body 8, and is supplied as hot water to the hot water supply equipment and the bath.

The home load system 3 includes a fuel cell equipment 5
In addition to the power supplied from the power supply via the main circuit line 11, the power is supplied from the power system 4 via the interconnection line 17 provided with the power meter 15 and the circuit breaker 16. I have.

As described above, in the conventional home fuel cell power generation system, the so-called self-powered system and the power purchase system are used in combination, and the spread thereof has been noted in an environment with economic advantages and extremely low exhaust gas pollutants. Watched.

[0013]

In the domestic fuel cell power generation system shown in FIG.
When a command is given from the control device 6 to each of the fuel cell equipment 5, the auxiliary system 2, and the household load system 3, a so-called fixed control operation in which the output is changed in a fixed manner or in a schedule according to a time zone is performed. ing.

However, in the case of a home fuel cell power generation system, when the power consumption of the home load system 3 falls below the amount of power supplied from the fuel cell equipment 5, a reverse power flow occurs on the power system system 4 side.

At this time, if a contract is made with the power company for "no reverse power flow", the reverse power flow relay is activated, the home load system 3 or the fuel cell equipment 5 is cut off from the power system 4, and an accident occurs. Become a factor.

On the other hand, when a contract is made with "reverse power flow", the reverse power flow relay does not operate, but the power flow from the power company due to the reverse power flow (payback).
However, there is usually a problem that the fuel cost is significantly lower and an economic loss is caused.

Therefore, when introducing a fuel cell power generation system for home use, how to maintain the maximum utilization while preventing reverse power flow of power, that is, how to keep the output of the fuel cell constantly high Is an important issue for future development.

An invention based on such technical intent is:
Not yet disclosed. However, in the field of rotating electrical machines,
For example, Japanese Unexamined Patent Publication Nos. 2000-166100 and 11-299110 disclose reverse flow prevention techniques, but it is difficult to apply the technique directly to the field of fuel cells due to the characteristics of products.

The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a fuel cell power generation system which is designed to prevent a reverse flow of electric power and to maintain an electric power utilization to a maximum. With the goal.

[0020]

According to the present invention, there is provided a fuel cell power generation system for achieving the above object.
As described in the above, the load system, while supplying the power from the fuel cell facility and the power from the power system, and having an auxiliary system that utilizes heat generated from the fuel cell facility, while the fuel cell facility A fuel cell power generation system including a control device for controlling the auxiliary system and the load system, wherein the control device includes means for capturing a received power value for supplying power to the load system from the power system system. It is.

[0021] In the fuel cell power generation system according to the present invention, in order to achieve the above-mentioned object, as described in claim 2, the control device, based on the received power value taken from the power system, It has an auxiliary power adjustment system for controlling the auxiliary system, a load adjustment system for controlling the load system, and a power generation end output adjustment system for controlling the power generation end of the fuel cell equipment.

Further, in the fuel cell power generation system according to the present invention, in order to achieve the above object, as described in claim 3, the auxiliary power adjustment system is provided when the power consumption of the load system decreases. A PID calculation device that compares a received power value taken from a power system with a preset value and, when a deviation is found, performs at least one of proportional, integral, and differential calculations based on the deviation. And an auxiliary equipment power adjustment control unit that supplies an arithmetic signal from the PID arithmetic unit to the auxiliary system as a control command.

According to a fourth aspect of the present invention, in the fuel cell power generation system according to the present invention, when the power consumption of the load system is reduced, the load adjustment system may be connected to the power system. A PID calculation device that compares the received power value taken from the system with a preset value and, when a deviation is found, performs at least one or more of the following operations based on the deviation: proportional, integral, and derivative; And a load adjustment control unit for giving a calculation signal from the PID calculation device to the load system as a control command.

According to a fifth aspect of the present invention, in the fuel cell power generation system according to the present invention, when the load adjustment system receives an operation signal from the auxiliary power adjustment system, the load adjustment system receives the operation signal from the auxiliary power adjustment system. , With a delay element.

Further, in order to achieve the above object, the fuel cell power generation system according to the present invention, when the power consumption of the load system is reduced, when the power consumption of the load system is reduced. A PID calculation device that compares a received power value taken from a power system with a preset value and, when a deviation is found, performs at least one of proportional, integral, and differential calculations based on the deviation. And a power-generating-end output adjustment control unit that gives a calculation signal from the PID calculating device to a power-generating terminal of the fuel cell equipment as a control command.

According to a seventh aspect of the present invention, in the fuel cell power generation system according to the present invention, the power generation end output adjustment system receives a calculation signal from the load adjustment system. , A change rate limiter.

Further, in the fuel cell power generation system according to the present invention, in order to achieve the above-mentioned object, as described in claim 8, the control device controls the fuel cell power generation system from the fuel cell equipment during power consumption increase of the load system. Means are provided for lowering the output rising speed for supplying power to the load system and increasing the power supply decreasing speed given to the load system from the fuel cell equipment while the power consumption of the load system is decreasing.

In order to achieve the above object, the fuel cell power generation system according to the present invention is characterized in that the load system is for domestic use.

Further, in the fuel cell power generation system according to the present invention, in order to achieve the above object, as described in claim 10, the auxiliary system uses the heat of the fuel cell equipment to generate heat from the hot water tank. A heat exchanger that heats the water through a circulation pipe, a hot water supply pipe that supplies hot water in the hot water storage tank to heat utilization equipment, and at least one or more of the circulation pipe, the hot water storage tank, and the hot water supply pipe And a heater provided in the above.

Further, in the fuel cell power generation system according to the present invention, in order to achieve the above-mentioned object, the circulation pipe is provided with a pump.

[0031]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a fuel cell power generation system according to an embodiment of the present invention.

FIG. 1 is a schematic system diagram showing an embodiment of a fuel cell power generation system according to the present invention applied to home use.

The fuel cell power generation system according to this embodiment includes a fuel cell power generation plant system 20, an auxiliary system 21 as ancillary equipment, and a home load system 22 that consumes home electricity.
And a power system 23.

The fuel cell power plant system 20 includes a fuel cell facility 24 and a control device 25.

The fuel cell equipment 24 includes a fuel processing system 26 such as a reformer, a fuel cell main body 27, an inverter 2
8. A circuit breaker 29 is provided. The fuel supplied to the fuel processing system 26 is reformed into hydrogen, and the reformed hydrogen is subjected to a chemical reaction by adding oxygen in the fuel cell main body 27 to generate electricity generated at that time. The AC power is converted by an inverter 28, and the converted AC power is supplied to the household load system 22 via a circuit breaker 29 and a main circuit line 29a.

On the other hand, the auxiliary system 21 includes a heat exchanger 30, a circulation pipe 31, a pump 32, a hot water storage tank 35, a hot water supply pipe 34, and heaters 35a, 35b, 35c, and circulates water in the hot water storage tank 33 with the pump 32. While circulating through the heat exchanger 30 through the pipe 31, the fuel is heated by heat from the fuel processing system 26 and the fuel cell main body 27 of the fuel cell facility 24, and is turned into hot water through a hot water supply pipe 34 to supply hot water or a hot water supply facility To be supplied.

The household load system 22 includes, in addition to electricity supplied from the fuel cell facility 24 via the main circuit line 29a, a power meter 36 and a circuit breaker 37 from the power system system 23.
This is used in combination with a so-called power purchase system in which power is supplied via an interconnection line 38 having

The control device 25 of the fuel cell power plant system 20 is connected to a power meter 36 provided on a connection line 38 of the power system 23 via a power value signal line 36a. When a sign of reverse power flow occurs, a command is received from the power meter 36 via the power value signal line 36a, and a control command is issued to each of the fuel cell equipment 24, the auxiliary system 21, and the household load system 22. ing.

Further, as shown in FIG. 2, the control device 25 sets the reverse power flow prevention margin in advance, and
Adder / subtractor 41 that compares the output from the power supply 9 with the output from the power receiving power unit 40 that purchases and receives the power from the power system 23.
When a sign of a reverse power flow appears, an auxiliary power adjustment system 42 for controlling the auxiliary system 21 shown in FIG. 1, a home load adjustment system 43 for adjusting the home load system 22 next, and further, ,
The fuel cell system 24 includes a power generation terminal output adjustment system 44 for controlling the output of the inverter 28.

The auxiliary power adjusting system 42 includes a PID arithmetic unit 4
5a, an integrating section 46a, an auxiliary power adjustment control section 47,
It is designed to operate first when signs of reverse power flow appear.

The home load adjustment system 43 includes a PID calculation unit 45b, an integration unit 46b, and a home load adjustment control unit 4.
8 to back up insufficient adjustment of the auxiliary machine power adjustment system 42.

The power-generating-end output adjustment system 44 includes a PID calculation device 45c, an integrating unit 46c, and a power-generating-end output adjustment control unit 4.
9 to back up insufficient adjustment of the auxiliary power adjustment system 42 and home load adjustment system 43 described above.

A delay element 50 is provided between the auxiliary power adjustment system 42 and the home load adjustment system 43. Further, a change rate limiter (rate limiter) 51 is provided between the home load adjustment system 43 and the power generation end output adjustment system 44.

The control constants are set to be the earliest in the domestic load adjustment control section 48 and the latest in the power generation end output adjustment control section 49.

The operation of the fuel cell power generation system having such a configuration will be described.

Normally, when the power consumption of the household load system 22 is constant, the power generation end output adjustment control unit 49 of the control device 25 shown in FIG. 2 controls the inverter 28 of the fuel cell equipment 24 shown in FIG. It does not control the auxiliary system 21 and the home load system 22 only by controlling.

When the power consumption of the home load system 22 significantly decreases from this state, the control device 25 operates as follows.

First, the power system 23 shown in FIG.
When the value of the power supplied to the receiving power unit 40 shown in (1) rapidly decreases, the control device 25 compares the output from the receiving power unit 40 with the setting value from the setting unit 39 by the addition / subtraction unit 41, and compensates for the deviation. This is given to the machine power adjustment system 42. The auxiliary power adjustment system 42 performs at least one of proportional, integral, and differential calculations in the PID calculation device 45a based on the deviation, and outputs the calculation signal integrated by the integration unit 46a to the auxiliary power adjustment control unit 47. , Where a control command is generated, and the control command is provided to the auxiliary system 21 shown in FIG. 1 for control. Specifically, when hot water is being used, the heater 35c provided in the hot water supply pipe 34 is controlled to increase power consumption. Also,
When the heater 35c provided in the hot water supply pipe 34 is not used, the heater 35a provided in the circulation pipe 31 or the hot water storage tank 33 is used.
Is controlled to increase power consumption. At this point, the home load adjustment system 43 does not operate immediately because the home load adjustment system 43 includes the delay element 50 and the power generation end output adjustment system 44 includes the change rate limiter 51.

Next, even if the power consumption of the auxiliary system 21 is transiently increased, the power to be supplied from the power system system 23 to the interconnection line 38 is predetermined without the sign of the reverse power flow disappearing. When the power meter 36 detects that it has not returned to the set value, the power meter 36 outputs the command to the power value signal line 3.
The power is supplied to the power receiving power unit 40 of the control device 25 through 6a.

The receiving power unit 40 directly transmits the command signal
Home load adjustment system 43 and indirectly auxiliary power adjustment system 4
2 and the delay element 50 to the home load adjustment system 43, where the PID calculation device 4
5b, and outputs the calculated signal to the home load adjustment controller 4.
8 to control the home load system 22. The home load system 22 transiently increases power consumption by, for example, activating a refrigerator.

If the adjustment is still insufficient, the control device 25 finally sends a control command from the power generation end output adjustment control unit 49 of the power generation end output adjustment system 44 to the inverter 28 of the fuel cell equipment 24 shown in FIG. The power supply from the power system system 23 to the interconnection 38 is restored to a predetermined value by controlling the inverter 28.

FIG. 3 shows that when the power consumption of the household load system 22 is significantly reduced, the received power unit 40, the auxiliary power adjustment control unit 47 incorporated in the control unit 25 of the fuel cell power plant system 20, It is the diagram which compared each behavior of load adjustment control part 48 and power generation end output adjustment control part 49.

From these behavior comparison diagrams, it can be seen that the auxiliary system 21, the home load system 22, and the fuel cell Since the power generating end 24, specifically, the inverter 28 shares and loads and adjusts the power consumption, it has been found that reverse flow of power from the fuel cell equipment 24 to the power system 22 can be prevented.

As described above, in the present embodiment, the control device 25 of the fuel cell power plant system 20 is connected to the power meter 36 provided on the interconnection 38 of the power system 23 via the power value signal line 36a. , An auxiliary power adjustment system 42, a home load adjustment system 43, and a power generation end output adjustment system 4
4 when the power consumption of the home load system 22 is significantly reduced, the power output from the fuel cell equipment 24 is transiently transferred to the auxiliary system 21 and the home load by the control commands of the adjustment systems 42, 43, 44. Since the power is consumed and adjusted at the power generation end of the system 22 and the fuel cell facility 24, the reverse flow of power from the fuel cell facility 24 to the power system 23 can be reliably prevented.

In this embodiment, in order to prevent the reverse flow of electric power, the priority is controlled in the order of the auxiliary system 21 and the home load system 22. However, the present invention is not limited to this example. In such a case, if the heater of the hot water tank is not required, or the control priority is changed depending on the circumstances of the installation location,
The logic circuit which is not desired to be changed may be masked and used. Further, the control priorities may be switched depending on the season or time zone.

Further, in the present embodiment, when the power consumption of the household load system 22 is significantly reduced, a logic circuit for controlling the power generation end of the fuel cell equipment 22 is incorporated in the control device 25. However, this embodiment is not limited to this example. For example, the home load system 22
When the power consumption of the fuel cell equipment 22 rises, the fuel cell equipment 22 is operated at a low speed so that the output can reach the rating in about 5 minutes. A change rate limiter that operates at a high speed so that it can be reached in about one second may be incorporated in the control device 25 to simplify the configuration.

FIG. 4 is a diagram comparing behaviors of domestic power consumption and output of fuel cell equipment. In this embodiment,
When the power consumption of the home load system 22 rises, the fuel cell equipment 22
When the rate-of-change limiting device for operating the output increase of the fuel cell equipment 22 at a low speed to reduce the power consumption of the household load system 22 at a low speed is incorporated in the control device 25 to simplify the configuration, FIG. Home load system 2
It was confirmed that the output reduction of the fuel cell equipment 24 well followed the power consumption reduction of No. 2 and that the reverse power flow prevention was performed.

[0058]

As described above, in the fuel cell power generation system according to the present invention, when the power consumption of the load system decreases, the power output from the fuel cell equipment is transiently transferred to the auxiliary system,
Since the load system and the fuel cell equipment are equipped with means for sharing and adjusting the load, it is possible to reliably prevent the reverse flow of power from the fuel cell equipment to the power system and make the fuel cell equipment perform stable operation. As a result, the utilization rate of the fuel cell equipment can be improved under stable operation.

[Brief description of the drawings]

FIG. 1 is a schematic system diagram in which an embodiment of a fuel cell power generation system according to the present invention is applied to home use.

FIG. 2 is a control block diagram applied to the fuel cell power generation system according to the present invention.

FIG. 3 shows a fuel cell power generation system according to the present invention.
FIG. 4 is a behavior comparison diagram showing behaviors of a received power unit, an auxiliary power adjustment control unit, a domestic load adjustment control unit, and a power generation end output adjustment control unit.

FIG. 4 shows a fuel cell power generation system according to the present invention.
FIG. 3 is a diagram comparing behaviors of domestic power consumption and output of fuel cell equipment.

FIG. 5 is a schematic system diagram showing a conventional fuel cell power generation system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fuel cell power plant system 2 Auxiliary equipment 3 Household load system 4 Electric power system 5 Fuel cell equipment 6 Control device 7 Fuel processing system 8 Fuel cell main body 9 Inverter 10 Circuit breaker 11 Main circuit line 12 Pump 13 Hot water tank 14 Heat Exchanger 15 Power meter 16 Circuit breaker 17 Interconnection line 20 Fuel cell power plant system 21 Auxiliary system 22 Household load system 23 Power system system 24 Fuel cell equipment 25 Controller 26 Fuel processing system 27 Fuel cell body 28 Inverter 29 Shutdown Unit 29a Main circuit line 30 Heat exchanger 31 Circulation tube 32 Pump 33 Hot water storage tank 34 Hot water supply tube 35a, 35b, 35c Heater 36 Power meter 36a Power value signal line 37 Circuit breaker 38 Interconnection line 39 Setting device 40 Power receiving power unit 41 Addition / subtraction Part 42 Auxiliary equipment power adjustment system 43 Household load adjustment system 44 Power generation end output adjustment system 45 a, 45b, 45c PID calculation device 46a, 46b, 46c Accumulation unit 47 Auxiliary equipment power adjustment control unit 48 Domestic load adjustment control unit 49 Power generation end output adjustment control unit 50 Delay element 51 Change rate limiter

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Motohiro Takahashi 2-4, Suehirocho, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture Inside Keihin Works, Toshiba Corporation (72) Takayuki Kaneko 2-chome, Suehirocho, Tsurumi-ku, Yokohama-shi, Kanagawa No. 4 Toshiba Keihin Works Co., Ltd. 4th Street Inside Toshiba Keihin Works F-term (reference) 5H027 AA02 DD06 KK52 MM21

Claims (11)

[Claims] 1. A fuel supply system comprising: a load system that supplies power from a fuel cell system and power from a power system system; and an auxiliary system that uses heat generated from the fuel cell system. In the fuel cell power generation system including a control device for controlling the auxiliary system and the load system,
The fuel cell power generation system according to claim 1, wherein the control device includes a unit that receives a received power value for supplying power to the load system from the power system. 2. A control device, comprising: an auxiliary machine power adjustment system for controlling an auxiliary machine system, a load adjustment system for controlling a load system, and a power generation system for fuel cell equipment, based on a received power value taken from the power system system. 2. The fuel cell power generation system according to claim 1, further comprising a power generation terminal output adjustment system for controlling a terminal. 3. The auxiliary power adjustment system compares the received power value taken from the power system with a preset value when the power consumption of the load system decreases, and when a deviation is found, the deviation is calculated. A PID calculation device that performs at least one of the following operations based on the PID calculation, and an auxiliary power adjustment control unit that supplies a calculation signal from the PID calculation device to the auxiliary system as a control command. The fuel cell power generation system according to claim 2, wherein 4. The load adjustment system compares the received power value taken from the power system with a preset value when the power consumption of the load system decreases, and based on the deviation, when there is a deviation. , A PID operation device for performing at least one operation among proportional, integral and differential operations, and a domestic load adjustment control unit for giving an operation signal from the PID operation device to the load system as a control command. The fuel cell power generation system according to claim 2, wherein: 5. The fuel cell power generation system according to claim 2, wherein the load adjustment system includes a delay element when receiving the operation signal from the auxiliary power adjustment system. 6. The power-generating-end output adjustment system compares the received power value taken from the power system with a preset value when the power consumption of the load system is reduced. PID operation device that performs at least one of the following operations based on the following formulas: proportional, integral, and differential; The fuel cell power generation system according to claim 2, comprising: 7. The fuel cell power generation system according to claim 2, wherein the power generation end output adjustment system includes a change rate limiter when receiving an operation signal from the load adjustment system. 8. The control device, while the power consumption of the load system is increasing,
Means for lowering the output rising speed for supplying power from the fuel cell equipment to the load system, and for increasing the power supply decreasing speed given to the load system from the fuel cell equipment while the power consumption of the load system is decreasing. The fuel cell power generation system according to claim 1. 9. The fuel cell power generation system according to claim 1, wherein the load system is for domestic use. 10. An auxiliary system for supplying heat from a hot water storage tank through a circulation pipe by using heat of a fuel cell facility to heat water from a hot water storage tank, and supplying hot water from the hot water storage tank to a heat utilization facility. The fuel cell power generation system according to claim 1, further comprising: a hot water supply pipe; and a heater provided in at least one of the circulation pipe, the hot water storage tank, and the hot water supply pipe. 11. The fuel cell power generation system according to claim 10, wherein the circulation pipe includes a pump.