JP3378394B2 - Parallel operation device of fuel cell power plant - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a parallel operation system for a fuel cell power plant, and particularly to a parallel operation by arranging a plurality of small, low output type fuel cell power plants packaged at a site where there is a demand for electric power. The present invention relates to a parallel operation device of a fuel cell power plant suitable for

[0002]

2. Description of the Related Art Normally, electric power is generated by rotating a generator with a prime mover such as a steam turbine, and the generated drive energy is generated as AC power by the generator, and the generated AC power is supplied as it is to the demand side. This method has been adopted as the most convenient one from the generation of electricity to the consumption.

On the other hand, steam for driving a steam turbine or the like is generated by thermal energy obtained by burning a fuel such as oil or gas by a boiler or the like. This fuel energy is taken out as thermal energy and used as steam energy. It is disadvantageous in terms of efficiency to exchange it and extract it as electric energy. For this reason, in recent years, a fuel cell power generation method in which fuel is electrochemically changed and energy is directly extracted by a flow of electrons generated at the time of this electrochemical change has been attracting attention and adopted as one of energy-saving power generation. It's starting.

This fuel cell electrochemically reacts a supplied fuel and an oxidant to generate electric power, whose output is a direct current output, and when consumed in a specific area, this direct current is used. When it is consumed as it is and a large amount of electric power is provided as part of energy-saving production, it is converted into alternating current by a direct current-alternating current exchanger and supplied to the electric power system.

When electric power is supplied to a specific electric power demand in this way, a single plant that meets the electric power demand is newly manufactured and supplied with electric power, or a packaged low-power type on-site system is installed. One type fuel cell plant was installed near the site where there is a demand for power, and power was supplied by making up for the shortfall with power from the grid.

A conventional power generation method for this on-site fuel cell plant will be described below.

There are the following three types of conventional fuel cell plant operation methods, and the respective operation methods can be switched by the operation of the operator.

(1) Standby operation: An operation for supplying the DC converter output to the auxiliary equipment in the plant. (2) System linkage operation: Operation to supply the output of the DC exchanger to the system. (3) Single load operation: Operation in which the output of the DC exchanger is supplied to the single load regardless of the grid.

Referring to FIG. 18, which is a standard configuration diagram of a fuel cell plant, an electric output method of the fuel cell plant, the above-mentioned three kinds of operating methods, and a switching method thereof will be described.

The fuel cell plant 1 is roughly divided into a DC power generation section 2, a control device 3 and an AC output section 4. The control device 3 includes an electric control device 13, a process control device 14, and a common memory 20, the electric control device 13 controls the AC output unit 4, and the process control device 14 controls the DC power generation unit 2. .

First, the shift (1) to the standby operation will be described.

The fuel cell 12 in the DC power generation section 2 is controlled by the process controller 14 and causes an electrochemical change by the supplied fuel and air to generate a DC electromotive force. At this time, the electric control device 13 detects the voltage due to the DC electromotive force, and when the voltage is sufficient to activate the DC booster 11, activates the DC booster 11. The DC booster 11 further boosts the electromotive force generated in the fuel cell 12. This is done in order to increase the efficiency of conversion from direct current to alternating current by the direct current converter 10 which is activated after this.

When the DC booster 11 and the quadrature converter 10 are activated, the DC output 100 generated in the fuel cell 12 is converted into the AC output 101. After that, when the AC output voltage reaches the rated value, the switch 21 is switched to the system side (B in the figure).
Side) to the orthogonal transformer 10 side (A side in the figure),
The output of the orthogonal transformer 10 is supplied to auxiliary machinery in the plant. At this time, the DC output 100 from the fuel cell 12 becomes the DC output power obtained by adding the AC output power to the plant auxiliary equipment and the loss component of the orthogonal converter 10 and the like. Since the output voltage from the fuel cell 12 is constant, the direct current increases.

The switch 21 is on the system side (B side in the figure) until the AC output 101 is output, and supplies system power to auxiliary equipment in the plant.

As described above, the state in which power is supplied to the auxiliary equipment in the plant by the AC output 101 from the orthogonal converter 10 and the plant is maintained is called (1) standby operation. At this time, the single load operation circuit breaker 9 is "open", the system connection circuit breaker 18 is "open", and the internal connection circuit breaker 19 is "closed". Therefore, the load 6 is supplied with power from the grid 22.

Next, the case where (1) the standby operation is performed and (2) the system linkage operation is performed will be described.

First, in the fuel cell plant 1 in the standby operation state, when the operator selects the grid connection operation from the terminal connected to the electric control device 13, the plant is switched to (2) grid connection operation.

During the standby operation, since the circuit breaker 5 is in the "closed" state, electric power is supplied from the grid 22 to the load 6 via the internal connection circuit breaker 19. In this state, when the operator selects the system linkage operation from the terminal connected to the electric control device 13, the system linkage circuit breaker 18 in the AC output unit 4 is “closed”.
Becomes As a result, the single load operation circuit breaker 9 is “open”, the system connection circuit breaker 18 is “closed”, the internal connection circuit breaker 19 is “closed”, and the switching device 21 is on the orthogonal converter 10 side (A side in the figure). ) Is connected to.

Therefore, the AC output 101 of the orthogonal transformer 10
Is supplied to the load 6 by removing the plant auxiliary equipment, and the load 6 is supplied from both the grid 22 and the fuel cell plant 1. At this time, the fuel cell plant 1 has an AC output synchronized with the grid 22.

At the same time when the operator selects the system-linked operation from the terminal, the active power and the reactive power to be output from the fuel cell plant 1 are set. The electric control device 13 in which the active power and the reactive power are set by the operator operates the output voltage and the phase with respect to the orthogonal converter 10.
As a result, the active power and the reactive power set by the operator are output.

Next, (3) shift to single load operation will be described.

When the operator selects the single load operation from the terminal connected to the electric control device 13 in the fuel cell plant 1 in the standby operation state, the plant switches to (3) single load operation.

In the standby operation state, since the circuit breaker 5 is in the "closed" state, the load 6 is supplied with electric power from the grid 22. In this state, when the operator selects the single load operation from the terminal connected to the electric control device 13, the single load operation circuit breaker 9 in the AC output unit 4 becomes “closed” and the internal connection circuit breaker 19 becomes “open”. Become. As a result, the single load operation circuit breaker 9 is "closed", the system connection circuit breaker 18 is "open", the internal connection circuit breaker 19 is "open", and the switch 2
1 is connected to the orthogonal transformer 10 side (A side in the drawing).

Therefore, the AC output 101 of the orthogonal transformer 10
The electric power for which the plant auxiliary equipment is removed is supplied to the load 6. At this time, the load 6 is limited to a load capacity smaller than the rated output of the fuel cell plant 1.

Next, the control of the system linkage operation is shown in FIG.
Will be described with reference to.

First, a predetermined target voltage signal vB /
The deviation signal between R and the output signal of the DC booster 11 is calculated by the comparison means 87, and the deviation signal is controlled by the booster voltage control means 86 and the DC booster 11 so that the output signal of the DC booster 11 is the target voltage. The signal vB / R is followed. As a result, the DC output from the DC booster 11 is controlled by the target voltage signal vB / R and is input to the phase control means 83 (thick line in the figure).

In general, active power P and reactive power Q are expressed by the following equations (1) and (2).

[0028]   P = [Va.Vb sin .THETA.] / Z -------- (1)   Q = [Va. (Va-Vb) cos [theta]] / Z --- (2)

Here, Va: output voltage of the quadrature converter Vb: voltage of the system Z: impedance of connection between the quadrature converter and the system Θ: phase difference between output voltage waveform of the quadrature converter and voltage waveform of the system

From the above equations (1) and (2), it is understood that the active power P and the reactive power Q may be adjusted by adjusting the output voltage Va of the quadrature converter 10 and its phase Θ. From the above idea, control of the active power P and the reactive power Q is realized by the active power setting Pset and the reactive power setting Qset by the operator shown in FIG.

That is, the active power setting Pset and active power P (thick line in the figure) shown in the upper right of FIG.
Is input to the active power control means 81.
The signal obtained by the control calculation is input to the adding means 82.

Next, the system synchronization signal is fetched from the system 22 by the system synchronization signal generation means 91 (thick line in the figure).
This system synchronization signal and the output signal of the active power control means 81 are added by the addition means 82, and the phase control means 83 generates the phase Θ.

On the other hand, the reactive power setting Qset (lower right in the figure) set by the operator and the reactive power are input to the comparing means 88, and the obtained deviation signal is the reactive power control means 8.
4, the AC output voltage control constant% F is output to the voltage control means 85.

As a result, the switching transistor is turned on / off based on the phase Θ by the phase control means 83 and the voltage v by the voltage control means 85, and the PW shown in FIG.
An M wave (lower stage in the figure) is generated.

The PWM wave shown in FIG. 20 is turned on at the voltage v.
Is determined, and the transistor is turned on for the time interval of the rise of the PWM wave. At this time, the phase Θ operation can be performed by changing the rising timing of the 0 cross of the PWM wave, and the operation amount of the voltage v is operated by changing the ON time of the PWM wave. As a result, the average value of the AC output waveform as shown in the upper part of the figure is obtained.

By such control, the fuel cell plant 1
Supplies power in synchronism with the grid and further controls active power and reactive power.

Next, the control contents of the electric control unit 13 for controlling the quadrature converter 10 and the DC booster 11 during the standby operation and the single load operation will be described with reference to FIG.

First, the voltage control of the DC booster 11 will be described with reference to FIG.
The target voltage signal vB / R is the same as in the system linkage described in 9.
The deviation signal from the comparison means 87 is controlled by the booster voltage control means 86 so that the output signal of the DC boosting section 11 follows. The method for controlling the voltage of the DC booster 11 is the same as the method for system linkage.

In the single load operation, unlike the system linkage operation, active power control and reactive power control are not performed, but output voltage constant control is only performed. The reason is that the active power P and the reactive power Q required are uniquely determined by the components of the load connected to the orthogonal converter 10 during the load operation. That is, the size of the active power is determined by the size of the pure resistance load, and the size of the reactive power Q is determined by the size of the load of the inductance and the capacitor. Therefore, it is not necessary to control the quadrature converter 10 on the output side in this case, and when connecting the load capacity within the rating of the fuel cell plant 1, the quadrature converter 10 outputs the necessary electric power on the load 6 side. .

Since the plant under the single load operation does not need to synchronize the AC output with the system 22, the frequency can be held by the reference clock provided in the electric control device 13.

Thus, in the case of single load operation, the phase Θref generated from the reference clock and the comparison means 90
The AC output voltage control constant% F calculated by the% F calculating means 89 from the deviation signal of the output voltage v calculated by the above and the target voltage vi and the phase Θ generated by the phase controlling means 83.
2 and the voltage v generated by the voltage control means 85.
A PWM wave similar to that shown in 0 is generated. This PWM wave controls the orthogonal converter 10 to control the voltage of the AC output to a target value.

As described above, the conventional on-site type fuel cell plant has three kinds of operation methods of standby operation, system linkage operation, and single load operation, and the orthogonal converter control method is provided for each operation method. Instead, the power supply was as stable as possible to the power demand.

[0043]

However, as shown in FIG.
The conventional fuel cell plant 1 described above has the following problems.

First of all, a large amount of construction cost is required because it is necessary to arrange a special power transmission line at the site where there is a power demand for connecting to the system 22. In addition, during the system linkage operation of (2) above, in the fuel cell plant 1, the load 6
The power demand cannot be caught up and the shortage is compensated from the grid 22. Therefore, when the required load amount X of the load 6 and the rated capacity Y of the fuel cell plant 1 have a relation of X> Y, if the system abnormality occurs, the fuel cell plant 1 alone becomes overloaded and the fuel cell plant 1 is protected. Therefore, there is a problem that the fuel cell plant 1 is forcibly stopped and the power supply is completely stopped.

Secondly, in the case of (3) islanding operation, it is necessary that the relationship of X <Y is always established between the required load capacity X of the load 6 and the rated capacity Y of the fuel cell plant 1. Therefore, it was necessary to manufacture a dedicated fuel cell plant 1 having a margin commensurate with the maximum required load capacity of the load 6 and to install it on the site. In such a case, if the facilities are expanded and the power demand increases compared to the beginning, the power from the grid must be relied on, and even if the fuel cell plant 1 becomes unnecessary without the facilities for the load 6, the dedicated In the fuel cell plant 1, it was also difficult to take it to another site and divert it.

Therefore, an object of the present invention is to provide a parallel operation apparatus for a fuel cell power generation plant, which operates a plurality of fuel cell plants 1 in parallel according to the magnitude of a specific load.

[0047]

According to a first aspect of the invention, a plurality of fuel cell plants for a specific load are connected in parallel to form a power supply system, and each plant uses a direct current through a fuel cell. A DC power generation unit that generates a voltage, an AC output unit that has a quadrature converter that boosts the DC voltage generated by this DC power generation unit and converts DC to AC,
A process control device that controls each process amount in the DC power generation unit, and a slave master plant that determines one master plant leading among a plurality of plants according to the operation stop state of the plant and the rest depends on the master plant. Along with the plant, the load sharing control device that determines the load burden of each plant from the power demand of the specific load and the number of operating plants, and the AC output of the master plant to the specific load and the AC output of the slave plant. In order to synchronize the output of a synchronization signal that synchronizes with the AC output of the own plant when the own plant is the master plant, a synchronization signal switching device that takes in the synchronization signal of the master plant when the own plant is the slave plant, and orthogonal transformation The active power and the reactive power output from the device follow the respective load sharing amounts, and A PWM signal is generated so that the voltage output from the converter will be the target value of the master plant and that each plant will output an AC waveform of the same shape from the orthogonal converter synchronized with the synchronization signal to the master plant to the specific load. And a common memory for taking in the operating states of the respective plants and storing the operating states of all the plants.

According to a second aspect of the present invention, in the parallel operating system for a fuel cell power plant according to the first aspect, the load sharing control device takes in the operating or shutdown status of each plant from a common memory and follows a predetermined rule. Which plant should be given priority as the master plant is calculated by calculating the priority index of the own plant, which is expressed by the priority index, and the calculation unit that saves it in the common memory and the priority index of each plant from the common memory are input. The master plant determination unit that determines whether the own plant is a master plant or a slave plant based on the magnitude relationship of these priority indices, and saves it in a common memory, and the required amount of specific load fetched from the common memory and plant operation. A load sharing amount determining unit that calculates the load sharing amount of each plant according to a predetermined calculation from the number of units and saves it in a common memory will be provided. It is obtained by the.

According to a third aspect of the present invention, in the parallel operation system for a fuel cell power plant according to the first or second aspect, the electric control unit refers to the common memory and outputs a synchronization signal when the own plant is the master plant. While outputting, when the own plant is a slave plant, a synchronization signal processing device that temporarily fetches and outputs the synchronization signal from the master plant of another plant, and a bypass that the synchronization signal bypasses the synchronization signal processing device when the own plant is stopped or abnormal An electric control device monitor for outputting a signal is provided, and the synchronous signal switching device has an inlet side for inputting a synchronous signal and an outlet side for outputting, and the inlet side and the outlet side of each plant are mutually The synchronous signal transmission line that is connected and forms a closed loop so that the synchronous signal is transmitted to each plant, and the synchronous signal from the synchronous signal processing device. While uptake outputting, when the bypass signal is input, is obtained by so providing the synchronizing signal switching means for switching so as to bypass the synchronization signal.

The invention of claim 4 is the invention of claims 1 to 3.
In any one of the parallel operation devices of the fuel cell power plant described above, the electric control device fetches various data from the common memory and fetches the synchronization signal from the synchronization signal processing device when the own plant is the master plant or the own plant is the slave plant. When the synchronization signal input unit takes in the synchronization signal via the synchronization signal switching device, and the phase control signal is output in synchronization with the synchronization signal so that the amount of active power output from the orthogonal converter becomes the load sharing amount. The power phase control unit, the voltage control unit that outputs a voltage signal so that the voltage output from the quadrature converter becomes a voltage target value that is predetermined by the master plant, and the reactive power output from the quadrature converter is invalid. The active power phase control unit and the reactive power control unit that increases or decreases the DC output voltage of the DC boosting unit provided in the AC output unit so as to cover the power load. Is obtained by the provided a PWM wave generator outputting the orthogonal transformer to generate a PWM waveform from the phase control signal and the voltage control unit to input a voltage signal.

The invention of claim 5 is the first to fourth aspects of the invention.
In any one of the parallel operation devices of the fuel cell power plant described above, the process control device controls the fuel control valve according to an increase / decrease in the DC current, using the DC output current from the DC power generation unit as a target value by a predetermined function. The fuel flow rate control unit that increases / decreases the hydrogen in the reformed fuel, the steam ejector control unit that increases / decreases the mixing ratio of the steam amount and the hydrogen amount according to the increase / decrease in the DC output current and the change in the reformed hydrogen, and the DC output The burner air flow controller controls the burner air control valve to increase or decrease the amount of air to the burner according to the increase or decrease of the current, and the process air control valve to control the air to the air electrode according to the increase or decrease of the DC output current. A process air flow rate control unit that increases / decreases the flow rate, and a battery cooling water temperature control unit that controls the battery cooling water heater and the battery cooling water temperature control valve according to the increase / decrease in DC output current to increase / decrease the battery cooling water temperature. It is obtained as provided.

[0052]

According to the invention of claim 1, the master plant is determined as a leading plant by a predetermined rule among a plurality of plants in parallel operation, and the rest are slave plants. The load sharing amount of each plant is determined from the required amount. Then, in each operating plant, the active power amount output from the orthogonal converter is synchronized with the synchronization signal from the master plant so as to be the load sharing amount, and the output from the orthogonal converter is invalid. The electric power amount follows the load sharing amount, and further, the voltage output from the quadrature converter follows the master plant voltage target value. The control is performed so that the AC output waveform is output based on the. As a result, the outputs of the operating plants are all synchronized, and the loads of the plants are shared in proportion to the power demand of the specific load. Further, since the PWM patterns of the plants can be made the same, the active power, the reactive power, and the output voltage are the same in each plant, and thus it is possible to prevent the cross current during parallel operation. Further, even if one plant in parallel operation stops due to a failure or the like, the load sharing of each of the remaining plants can be changed, and the number of plants to be operated later can be increased during parallel operation. Therefore, it is not necessary to manufacture one dedicated plant for a specific load, and a plurality of general-purpose mass-produced plants can be used to meet the power demand and economical operation can be performed.

According to the second aspect of the present invention, a priority index indicating which operating plant is preferentially set as the master plant based on the operating or shutdown status of each plant and a predetermined rule. Is calculated, the master plant is determined from the magnitude relation of the index of this priority, and the rest are slave plants. Further, the load sharing amount per unit is calculated from the power demand amount of the specific load and the number of operating units, and these data are stored in the common memory. Thus, when the master plant fails and stops during parallel operation, the next master plant is immediately determined from the priority index of each plant, and smooth parallel operation is performed. Also, when the power demand of a specific load increases or decreases or the operating plant stops due to a failure, and when the stopped plant restarts operation, the load sharing amount is calculated,
Based on this, the power of each plant is output. Therefore, it is possible to reliably and reliably follow the power demand of the specific load during parallel operation.

According to the third aspect of the present invention, the synchronization signal generated in the master plant is transmitted to the slave plant via the synchronization signal transmission line, bypassed in the case of an abnormal or stopped plant, and restored to normal during the operation. When the operation is resumed, the synchronization signal is taken into the slave plant without bypassing. As a result, it is possible to supply the synchronized power to the plants without affecting the specific load even if the plants become abnormal, stop, or restart during parallel operation.

According to the fourth aspect of the present invention, the active power phase control section outputs the phase control signal so that the active power amount synchronized with the synchronization signal and output from the quadrature converter becomes the load sharing amount, and the voltage control is performed. Section outputs a voltage signal so that the AC output voltage becomes the target value of the master plant, and the reactive power control section outputs the DC power of the DC booster section so that the reactive power output from the orthogonal converter becomes the reactive power sharing amount. The voltage is controlled. Furthermore, from the phase control signal and the voltage signal, P
A WM waveform is generated. As a result, PW of each plant
The M waves have the same pattern, a cross current does not occur between plants, and stable power can be supplied to a specific load.

According to the fifth aspect of the present invention, each process amount is tracked by increasing or decreasing each process amount in the plant in advance in accordance with the increase or decrease of the DC output current output from the DC power generation unit. As a result, in parallel operation, the load sharing is likely to change, the AC output from the orthogonal converter changes, and the DC output current of the DC power generation unit fluctuates, but the process amounts change accordingly. Therefore, the load on the fuel cell is reduced and the entire plant is always stable.

[0057]

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

FIG. 1 is a block diagram of a parallel operating system for a fuel cell power plant showing a first embodiment of the present invention.

In the figure, a plurality of fuel cell plants 1 are connected to a bus bar 17 and connected to a load 6 via a circuit breaker 5.

Each fuel cell plant 1 comprises a DC power generation unit 2, a controller 3 and an AC output unit 4. The DC power generation unit 2 has a fuel cell 12 similar to that shown in FIG.
Is an electric control device 13, a process control device 14, a common memory 20, a load sharing control device 15, and a synchronization signal switching device 16.
And are provided so that parallel operation is possible.

The AC output unit 4 comprises a quadrature converter 10, a DC boosting unit 11 and a circuit breaker 9. The load sharing control devices 15 of the fuel cell plants 1 are connected to each other by the data transmission line 7, and the synchronization signal switching devices 16 are connected to each other by the synchronization signal transmission line 8.

Here, in the electric control device 13, the active power amount and the reactive power amount output from the orthogonal transformer 10 follow the respective load sharing amounts, and the voltage output from the orthogonal transformer 10 becomes the master plant. Together so that the target value of
Orthogonal converter 10 synchronized with the synchronization signal with the master plant
To a specific load, a PWM signal is generated so that each plant outputs an AC waveform of the same shape.

The process control device 14 controls each process amount in the DC power generation section 2.

The load sharing control device 15 determines one master plant leading among a plurality of plants according to the operation stop state of the plant and a predetermined rule, and the rest as slave plants subordinate to the master plant. The load burden amount of each plant is determined from the power demand of the specific load and the number of operating plants.

The synchronizing signal switching device 16 sends a synchronizing signal synchronized with the AC output of the own plant when the own plant is the master plant in order to synchronize the AC output output from the master plant to the specific load and the AC output of the slave plant. While outputting, it takes in the synchronization signal of the master plant when the own plant is a slave plant.

The common memory 20 is for taking in the operating states of the respective plants and storing the operating states of all the plants.

The operation of the load sharing control device 15 will be sequentially described with the above configuration. First, as shown in FIG. 2, the load sharing control device 15 is in the OFF state while the load sharing control device 15 is stopped, and the load is turned on by a power-on operation or the like. The sharing control device 15 enters the initialization state (in the direction of the arrow in the figure). When the initialization process ends, the state transits to the stopped state. In this state, if the electric control device 13 is stopped and is in the standby operation state described above, the load sharing control device 15 stays in the stopped state, and the electric control device 1
If 3 is the load operating state, the load sharing control device 15 transitions to the power generating state.

On the contrary, when the electric control device 13 is changed from the load operation to the standby operation or the stopped state for some reason such as a failure, the load sharing control device 15 is transited to the stopped state. Here, the electric control device 13 and the load sharing control device 15
Since various parameters including the mutual driving state are communicated via the common memory 20, the mutual driving state can be known.

Next, the processing by the load sharing control device 15 in the stopped state will be described with reference to FIG.

First, when the load sharing control device 15 is stopped, the load sharing control state writing process is performed, and the current stopped state, which is the state of the load sharing control device 15, is written in the common memory 20 (S1), and the priority is given. The priority number (PRI
_0) is set to "1" (S2).

Next, the priority number held by the load sharing control device 15 of each plant is received via the data transmission line 7 (S
3) The priority calculation process is performed, and the priority number of the user is recalculated (S4). Thereby, it is determined whether the own plant is the master plant or the slave plant (S5). By this master / slave determination processing, it is determined whether the own plant is the master or the slave, and the master flag (D_MASTER) is determined. This master flag is written in the common memory 20 by the master flag writing process (S6), and the operating state of the electric control device 13 is read from the common memory 20 (S7). As a result, it is determined whether or not the own plant is generating power (S
8).

If it is determined in this determination that the electric control device 13 is generating electric power, the process proceeds to the process in the electric power generating state shown in FIG. 4, and if not in electric power generating, the load sharing control state writing process (S
The process is returned to 1) and the process is repeated (S1 to S8). Note that, in FIG. 3, the processing indicated by the quadrangle double frame indicates access to the common memory 20, and the black triangle at the lower left corner of the quadrangle indicates transmission / reception to / from the data transmission path 7.

Next, the processing by the load sharing control device 15 in the power generating state will be described with reference to FIG.

If it is determined by the process shown in FIG. 3 that power is being generated, the process proceeds to the load sharing control power generation state writing process shown in FIG. 4 (S9). That is, in the load sharing control state writing process, the power generation state, which is the current state of the load sharing control device 15, is written in the common memory 20, and in the priority transmitting process, the data transmission line 7 is calculated by the previous priority calculation. The priority number of the self-generated plant is output (S1
0).

At this time, the fuel cell plant 1 is in a power generating state, and the electric control unit 13 controls the AC output unit 4. The electric control device 13 detects active power and reactive power output from the fuel cell plant 1 controlled by its own plant, and writes the detected active power and reactive power in the common memory 20 (S11). When the P and Q reading processing is performed, the electric control device 13 reads the active power P and the reactive power Q of its own plant written in the common memory 20 and transmits them to the data transmission line 7 (S1).
2).

Then, the active power P and the reactive power Q of the other plants in parallel operation, which are transmitted and received by the data transmission line 7, are received by the P, Q reception process (S13). Then, the average value of the active power is calculated from the active powers of the other plants and the active power of the own plant by the P and Q calculation processing. Further, the average value of the reactive power is calculated from the reactive power of the other plants and the reactive power of the own plant (S1).
4). The calculated active power and reactive power are common memory 2
It is written to 0 (S15). The values thus calculated become the target values of active power and reactive power for the electric control device 13.

Now, the method of calculating the active power and the reactive power described above will be described with reference to FIG. 5, which shows an example of operating three fuel cell plants 1 in parallel.

FIG. 5 shows the parallel operation of three fuel cell plants 1, FC # 1, FC # 2 and FC # 3, in which the load sharing control device 15 in the fuel cell plant 1 uses the data transmission line 7. Connected and transmitting data. In this transmission item, FC # 1 has active power P = a1 and reactive power Q.
= B1 output, FC # 2 shows active power P = a2, reactive power Q = b2 output, and FC # 3 active power P = a3. , Reactive power Q = b3 output.

These data are P, Q described in FIG.
Read processing unit (S11), P, Q transmission processing (S12)
FC and FC reception processing (S13)
The load sharing control device 15 in each of the plants # 1, FC # 2, FC # 3 calculates the load sharing amount by the following equations (3) and (4).

[0080] P = (a1 + a2 + a3) / 3 −−−− (3) Q = (b1 + b2 + b3) / 3 ----- (4)

This calculation is performed by processing step S1 shown in FIG.
4, the denominator “3” is the number of received data including the data of the own plant. This is passed as the target values of the active power P and the reactive power Q of each electric control device 13. In this way, in the load sharing control device 15, the total output of the plants in parallel operation is divided by the number of plants in parallel operation, and the power supply to the load is evenly shared by the plants in parallel operation.

Next, the processing of the synchronization signal switching device 16 will be described.

In general, the AC waveform is formed by the AC frequency and phase and the AC voltage. Among these, the frequency is uniquely defined at the time of manufacturing the plant from the preset place and load frequency. However, even if the frequencies of all the plants operating in parallel are the same, synchronization is not always possible, and a synchronization signal is required.

That is, the electric control unit 13 of the fuel cell plant 1, which is judged as the master plant by the master / slave judgment (S5) described in FIG. 3, detects the 0 cross from its output waveform, and detects from the position of the 0 cross. A rectangular wave having a predetermined rising width as shown in FIG. 6 is generated. This rectangular wave is sent to the synchronization signal switching device 16 in the fuel cell plant 1, and is sent to the synchronization signal switching device 16 in the fuel cell plant 1 determined as the slave plant via the synchronization signal transmission line 8. . Electric control device 1 in slave plant
In 3, the zero cross point of the AC output is matched with the rising edge of the rectangular wave received from this master plant. In this way, the master plant and other slave plants are synchronized.

Next, the AC output voltage control constant% F will be described with reference to FIG.

First, the load sharing control device 1 described with reference to FIG.
In the process of 5, the state of the electric control device 13 is read by the state reading process (S7). Load sharing control device 1
It is determined whether or not 5 is generating power (S21).
Based on the result of the master / slave determination process of FIG. 3, it is determined whether or not it is the master (S22).

If it is determined that the relevant plant is generating electricity and is a master plant, the AC voltage control constant (EXT_% F) is set to 0 (S23).
In the% F reading process, the AC output voltage control constant% F used in the own plant is read through the common memory 20 (S24), and the AC output voltage control constant% F is transferred to the data transmission line 7. It is sent (S25).

When the corresponding plant is generating electricity and is a slave plant, the AC voltage control constant (EXT_% F) is read from the data transmission line 7 and written in the common memory 20 (S26, S27). . As a result, the written AC output voltage control constant% F is passed to the electric control device 13 and used for AC output control.

As described above, all the plants in the parallel operation state during power generation use the AC output voltage control constant% F transmitted from the master plant to perform the AC output control, and therefore the AC having the same output voltage is output. It If the plant is not generating power, the AC voltage control constant (EXT
_% F) is initialized to 0 (S28).

FIG. 8 is an internal block diagram showing a load sharing control device 15 provided in a parallel operating system of a fuel cell power plant showing a second embodiment of the present invention.

The load sharing control device 15 includes a calculation unit 31.
And master plant determining unit 32 and load sharing amount determining unit 33
And a data transmission line 7 in the common memory 20, respectively.
Connected by.

Here, the calculation unit 31 fetches the operating or shutdown status of each plant from the common memory 20 and indicates which plant is to be preferentially designated as the master plant according to a predetermined rule by the priority index. The priority index of is calculated and stored in the common memory 20.

The master plant determining section 32 inputs the priority index of each plant from the common memory 20, determines whether the own plant is a master plant or a slave plant based on the magnitude relation of these priority indexes, and then uses the common memory. 20
It is something to save.

The load sharing amount determining unit 33 is arranged in the common memory 20.
The load sharing amount of each plant is calculated according to a predetermined calculation from the required load of the specific load and the number of operating plants, which are stored in the common memory 20.

With the above configuration, the processing of the calculation unit 31 and the master plant determination unit 32 will be described with reference to FIG. 9. First, the calculation unit 31 determines whether the plant is in operation or stopped. (S31). With this judgment,
When operating, the priority order number indicating the index of priority is not calculated (the priority order number of the operating plant is unchanged). When the plant is stopped, it is determined whether or not a priority number is received from another plant (S32).

When the priority number is received in this determination, the own priority number (PRI_0) is set to "the maximum value of the received priority number + 1" (S33). If you do not receive it, your own priority number (PRI
_0) is set to "1" (S34). At this stage,
The current priority number of the plant is determined.

Next, the master plant determining unit 32 determines whether or not the priority number (PRI_0) of the plant is the minimum priority number of all plants (S35). In the case of the minimum value in this determination, the plant becomes the master plant (S36). If it is not the minimum value, it becomes a slave plant (S37).

Here, the transition of the priority number will be described by taking a system composed of three plants as shown in FIG. 10 as an example.

First, assuming that all plants are in a stopped state, first, since all plants are stopped, all priority numbers are set to "1" (step 1). Next, consider the case where only the plant 1 is put into operation. At this time, the plant 1 transmits its own priority number to all the other plants. Along with this, the plants 2 and 3 receive the priority number “1”, and “2” obtained by adding “1” to the priority number “1” of their own is the plant 2 and the plant 3.
(Step 2).

Further, when the plant 2 is also put into operation, the plant 3 receives the priority number "1" from the plant 1 and the priority number "2" from the plant 2. Therefore, the priority number of the plant 3 becomes "3" which is obtained by adding "1" to the maximum value "2" of the received priority numbers (step 3).

Thereafter, the priority number of each plant is changed according to the same rule. Finally, when all the plants are stopped again, the transmission of the priority number is lost (the priority number is not received), and the priority numbers of all the plants are reset to "1". The plant with the lowest priority number becomes the master plant of the system.

For example, in the range surrounded by the alternate long and short dash line in FIG. 10, the priority number of the plant 1 is "1" and the plant becomes the master plant, the priority number of the plant 2 is "2", and the priority number of the plant 3 is Is "3", the state becomes a slave, and three units are operating in parallel (step 4). When the plant 1 is stopped from this state, the load sharing control device 15 of the plant 2 continues to operate, so the determination (S31) of FIG. 9 by the plant 2 is NO, and all the processes of the calculation unit 31 are performed. Bypass. The plant 2 determines in the master plant determining unit 32 that the priority number of its own plant is the minimum value among the received priority numbers. Therefore, since the plant 2 is the master plant (D_
MASTER) flag is set (step 5). At this time, the calculation unit 31 determines that the plant 1 in the stopped state is in the stopped state, and since there is a priority number from other plants, YES is selected and a new priority number “4” is assigned. (Step 6). further,
If the plant 2 is stopped, the priority number of the plant 2 becomes "4" by adding "1" to "3" input from the plant 3 in step 4 (step 7). When all plants are stopped, the priority number is "1"
Becomes

Incidentally, the thick frame in the drawing shows the master plant.

As described above, according to the second embodiment, when a plurality of plants are sequentially activated, each plant has a priority number in the order in which they are activated.
Thereby, the master plant can be determined.
Further, when the master plant in parallel operation stops, the master-slave switching can be smoothly performed by instantly determining the master plant from other operating plants.

FIG. 11 is a block diagram showing a synchronous signal switching device and an electric control device provided in a parallel operating system of a fuel cell power plant showing a third embodiment of the present invention.

The sync signal switching device 16 includes a sync signal bypass b contact 40, a sync signal input a contact 41, a sync signal output a contact 42, and a sync signal switching relay 43 for opening and closing these.
It is composed of Further, the electric control device 13 includes an electric control device monitor 44 and a synchronization signal processing device 45.

Here, the sync signal bypass b contact 40 is
When the sync signal switching relay 43 is excited, it is opened, and when it is not excited, it is closed, and the sync signal bypass route 5
Form 0 line. The sync signal input a contact 41 and the sync signal output a contact 42 are closed when the sync signal switching relay 43 is excited, and form a line of a sync signal input route 48 and a sync signal output route 49. The synchronization signal switching relay 43 is excited when the electric control device 13 is normal, and is non-excited when the electric control device 13 is abnormal or stopped.

The electric control unit monitor 44 outputs a synchronization signal processing unit 45 for the synchronization signal when the own plant is stopped or abnormal.
The synchronous signal switching relay 43 is de-energized so as to bypass. The synchronization signal processing device 45 refers to the common memory 20 and outputs a synchronization signal when the own plant is a master plant, and when the own plant is a slave plant, temporarily fetches the synchronization signal from the master plant of another plant and outputs it by-pass.

With the above configuration, the synchronization signal switching relay 43 is connected to the electric control device monitor 44 in the electric control device 13 and is excited during normal operation, and is not excited during plant stop or abnormal condition. As a result, under normal conditions, the electrical control device monitor 44 excites the synchronization signal switching relay 43, the synchronization signal bypass b contact 40 opens, and the synchronization signal input a
The contact 41 and the sync signal output a contact 42 are closed. Therefore, a closed loop line is formed which includes the synchronization signal input route 48 and the synchronization signal output route 49 connected to the synchronization signal input unit 46 and the synchronization signal output unit 47 of the synchronization signal processing device 45. This closed loop serves as a synchronization signal input / output route for the normal fuel cell plant 1 or a normal fuel cell plant that has started up later.

On the other hand, when the electric control device 13 is abnormal, the electric control device monitor 44 deenergizes the sync signal switching relay 43, the sync signal bypass b contact 40 is closed, and the sync signal input a contact 41 and the sync signal output a. The contact 42 is opened. As a result, a line is formed by the sync signal bypass route 50. Therefore, when the plant is abnormal, the synchronization signal can be bypassed to the next plant as it is.

Next, when there are a total of three fuel cell plants 1 including one master plant and two slave plants, the plant that started first and became the master is the synchronization signal in the electric control unit 13. The synchronization signal output unit 47 of the processing device 45 transmits the synchronization signal through the synchronization signal output route 49.

The synchronizing signal output from the master plant passes through the synchronizing signal transmission line 8 to the next slave plant # 1.
Is sent to (middle row in the figure). If this plant is stopped or abnormal, the synchronization signal switching relay 43 connected to the electric control device monitor 44 is non-excited, so that the synchronization signal passes through the synchronization signal bypass route 50 to the next slave plant # 2. Bypassed (lower part in the figure).

If the slave plant # 1 is normal or normal even if it starts up later, the synchronous signal switching relay 43 connected to the electric control device monitor 44 is excited. Therefore, the sync signal transmitted from the master plant is input to the sync signal input unit 46 of the sync signal processing device 45 through the sync signal input route 48. Slave plant # 1 can perform AC output phase control by this synchronization signal and generate an AC output synchronized with the master plant.

Further, the synchronization signal of the master plant input to the synchronization signal input unit 46 is returned by the synchronization signal processing device 45, passed from the synchronization signal output unit 47 through the synchronization signal output route 49 to the next slave plant # 1. Similarly, AC output control is performed by the transmitted synchronization signal to generate an AC output synchronized with the master plant.

Next, an AC output synchronizing method in the electric control devices 13 of the slave plant and the master plant will be described with reference to FIG.

The synchronous signal switching contact 51 in the synchronous signal processing device 45 is switched to the reference signal generator 52 side when the plant is the master. As a result, the synchronizing signal input from the outside is cut off and the output is controlled by the self-oscillator. If it is not the master, the synchronization signal input section 4
It is switched to the 6 side and the sync signal is taken in.

First, in the case of the master plant, the sync signal switching contact 51 in the sync signal processing device 45 is switched to the reference signal generator 52 side. The phase signal oscillated by the reference signal generator 52 by this switching is transmitted to the synchronization signal output unit 47 in the phase comparator 54 of the PLL circuit 53. On the other hand, it is directly transmitted to the slave plant via the synchronization signal output route 49 as a synchronization signal. The synchronization signal input to the phase comparator 54 in the PLL circuit 53 controls the phase of the AC output according to the phase fed back from the voltage control oscillator 55. That is, the AC output waveform of the own plant is taken into the PLL circuit 53 from the outside, and it is compared by the phase comparator 54 whether the synchronizing signal and the AC output waveform are synchronized, and the phase is controlled by means not shown.

In the case of a slave plant, the sync signal switching contact 51 in the sync signal processing device 45 is switched to the sync signal input side. By this switching, the sync signal received from the sync signal input route 48 is input. This sync signal is transmitted to the phase comparator 54 in the PLL circuit 53 and the sync signal output unit 47 in the sync signal processing device 45. The former synchronizing signal is used as a phase signal for the phase control of the AC output as in the case of the master plant. The latter sync signal is transmitted as it is to the next slave plant via the sync signal output route 49 as a sync signal.

By the above synchronizing signal transmission / reception method, the stopped plant or abnormal plant can be bypassed and the AC waveforms output from each plant can be synchronized.

FIG. 13 is a block diagram of an electric controller provided in a parallel operating system of a fuel cell power plant showing a fourth embodiment of the present invention.

In the figure, the electric control unit 13 comprises a synchronizing signal input section 34, an active power phase control section 35, a voltage control section 36, a reactive power control section 37 and a PWM wave generating section 38.

Here, the synchronizing signal input unit 34 fetches each data from the common memory 20 and fetches the synchronizing signal from the synchronizing signal processing device 45 when the own plant is the master plant, or when the own plant is the slave plant, the synchronizing signal switching device. The synchronizing signal is taken in through 16.

The active power phase control section 35 outputs the phase control signal in synchronization with the synchronization signal so that the active power output from the orthogonal converter 10 becomes the load sharing amount.

The voltage control section 36 controls the voltage from the orthogonal transformer 10 so that the target value of the own plant is the target value of the master plant when the own plant is the master plant. Thus, the voltage from the orthogonal transformer 10 is controlled.

The reactive power control unit 37 increases or decreases the DC output voltage of the DC boosting unit 11 provided in the AC output unit 4 so that the amount of reactive power output from the orthogonal converter 10 becomes the reactive power burden amount. .

The PWM wave generator 38 inputs the phase control signal from the active power phase controller 35 and the voltage signal from the voltage controller 36, generates a PWM waveform and outputs it to the orthogonal transformer 10. .

Next, the operation of the electric control unit 13 shown in FIG. 13 will be described with reference to FIG.

FIG. 14 is a control block diagram showing a state in which two plants, FC # 1 and FC # 2, are operated in parallel. Here, FC # 1 is a master plant, FC # 2 is a slave plant, and FC # 1 and FC # 1 are FCs.
# 2 Active energy and reactive energy required for the plant are
As described with reference to FIG. 4, it is calculated by the P and Q calculation processing in the load sharing control device 15, respectively.

Next, the calculated active power setting Pave of FC # 1 is compared with the active power of the current output by the comparison means 80, and the active power control means 81 determines the operation amount of the phase corresponding to the deviation signal by the comparison means 80. It is calculated. In addition,
The active power control means 81 has upper and lower limit values in order to suppress an excessive amount of phase operation, and limits the operation amount.

On the other hand, since FC # 1 is a master plant, the output phase is output by the phase calculated from its own clock. Therefore, the reference phase Θref1 generated from the internal clock is passed as a synchronization signal to another FC # 2 plant via the synchronization signal transmission line 8. The operation amount of the phase of FC # 1 is calculated by adding Θref1 and the phase operation amount calculated by the active power control means 81 by the addition means 82.

Since FC # 1 is a master plant, the output voltage as well as the phase is output according to the output power target value internally held. Comparing means 9 between the output voltage target value vi1 inside the electric control device 13 and the voltage currently being output.
The deviation is calculated by 0, and the AC output voltage control constant% F corresponding to this deviation is calculated by the% F calculating means 89.
Then, the AC output voltage control constant% F is passed to FC # 2 via the data transmission line 7.

In FC # 1, the phase operation amount added by the addition means 82 and the AC output voltage control constant% F calculated by the% F calculation means 89 are passed to the phase control means 83 and the voltage control means 85, respectively. The PWM wave described above is generated and used as the operation amount of the orthogonal converter 10.

On the other hand, FC # 2 which is a slave plant
Is a deviation between the active power setting Pave calculated by the P and Q calculations in the load sharing control device 15 and the active power P2 currently being output, and the active power control means 81 outputs a manipulated variable having a phase corresponding to the deviation. . Further, the reference phase input from FC # 1 is added by the addition means 82, and the amount of phase operation is output to the phase control means 83.

Further, the voltage manipulated variable is obtained from the AC output voltage control constant% F passed from FC # 1 via the data transmission line 7. These phase manipulated variable and AC output voltage control constant% F
PWM by phase control means 83 and voltage control means 85
A wave is generated and becomes an operation amount for the orthogonal transformer 10.
Therefore, the PWM waves of FC # 1 and FC # 2 are generated with the same AC output voltage control constant% F and the same reference phase. As a result, the required active power is controlled for both FC # 1 and FC # 2. However, the difference is the amount of phase operation calculated by the active power control means 81. This amount of phase manipulation is generated during the transition of operating the active power.

Next, when controlling the reactive power, the reactive power request value Qave calculated by the P and Q calculations in the load sharing control device 15 is compared with the current reactive power output Q1 by the comparing means 88 and the reactive power is compared. The control unit 92 calculates the voltage operation amount of the DC booster 11. The reactive power control means 92 limits the output voltage operation amount.

This voltage operation amount is added to the reference voltage vB / R of the DC booster 11 by the adding means 93 to obtain the voltage target value of the DC booster 11. The deviation between the voltage target value and the current voltage value is calculated by the comparison means 87, and the operation amount for the DC booster 11 is generated by the booster voltage control means 86 according to the output thereof.

Thus, the reactive power control is performed by the orthogonal transformer 1.
It is realized by operating the voltage of the DC booster 11 instead of operating the voltage of 0. That is, the orthogonal transformer 1
By operating the voltage of the DC booster 11 instead of operating the voltage of 0, the input voltage to the orthogonal transformer 10 is changed.

Next, when FC # 1 which is the master plant is stopped for some reason, the master flag is set to F.
It is written in the common memory 20 in C # 2. The electric control device 13 in FC # 2 recognizes that it has become the master plant. As a result, the switching means 94 is switched, and the AC output voltage control constant% F calculated by the own% F calculation means 89 is output from the voltage control means 85 and PW.
M waves are generated. Further, this AC output voltage control constant% F is output from the voltage control means 85, and the voltage control means 8
At 5 the data is transmitted to the data transmission line 7.

Further, in the switching means 95, when the own plant is recognized as the master plant, the synchronizing signal transmission line 8
The reference phase Θref2 in the electric control unit 13 is used instead of the rectangular wave from the power control unit 8 and the addition unit 82 adds the phase operation amount from the active power control unit 81 to add the phase control unit 8
A PWM wave is created by the signal generated by 3. Further, this reference phase Θref2 is the synchronization signal transmission line 8
Sent to.

FIG. 15 is a block diagram of a parallel operating system for a fuel cell power plant showing a fifth embodiment of the present invention.

The fuel cell plant 1 is composed of a DC power generation unit 2, a control device 3 and an AC output unit 4, and the control device 3 is
It is composed of an electric control device 13 and a process control device 14. The DC output 100 from the DC power generation unit 2 is detected by the DC current detector 102 and input to the process control device 14. The DC power generation unit 2 is configured to be controlled by the process control signal 104 from the electric control device 13.

FIG. 16 shows a system diagram of a fuel cell plant to which the fifth embodiment is applied, and FIG. 17 is a concrete configuration diagram of a process control device showing the fifth embodiment.

First, in the fifth embodiment, as shown in FIG. 16, the fuel flow rate detector 122 is arranged at the outlet side of the fuel control valve 110 of the fuel supply system, and the vapor ejector opening detector 123 is provided at the vapor ejector 112. Further, the reformer temperature detector 124 is arranged in the reformer 113. Further, in the air supply system, the burner air control valve 116 and the burner air flow rate detector 125 are arranged on the inlet side of the combustor 115, and the process air control valve 117 and the opening degree detector on the inlet side of the air electrode 12B of the fuel cell 12. 126 and are arranged.

Further, in the battery cooling water system, the battery cooling water temperature detector 127 is arranged on the inlet side of the battery cooling water heater 118.

Each of the detectors described above is shown in FIG.
Fuel flow rate controller 7 provided in the process controller 14 shown in FIG.
1 and the steam ejector control unit 72, the burner air flow rate control unit 73, the process air flow rate control unit 74, and the battery cooling water temperature control unit 75, respectively.

In the fuel flow rate control unit 71, the DC current signal detected by the DC current detector 102 is input to the function unit 71a and converted into the target temperature of the reformer 113. The deviation between the target temperature and the amount detected by the reformer temperature detector 124 is calculated by the deviation calculator 71c. Then, in the multiplication unit 71d, the deviation signal obtained in the deviation calculation unit 71c is multiplied by the DC current signal of the DC current detector 102.

The obtained signal becomes the target value of the fuel flow rate in the fuel flow rate control section 71. The deviation between the target value and the observed amount detected by the fuel flow rate detector 122 is calculated by the deviation calculator 71e. The control calculation unit 71f calculates a control amount based on this deviation, and the fuel control valve 110 is opened / closed by the obtained control amount. The fuel flow rate is controlled by opening and closing the fuel control valve 110.
By this control, when the DC output 100 current increases, the amount of hydrogen supplied to the reformer 113 is increased in advance according to a predetermined function, and conversely, when the DC output 100 current decreases, the hydrogen is supplied. Hydrogen content is reduced.

In the steam ejector control section 72, the target value of the fuel flow rate in the fuel flow rate control section 71 is input to the function section 72a and converted into the target value of the opening degree of the steam ejector 112. The deviation calculator 72b calculates the deviation between this target value and the detection amount detected by the steam ejector opening degree detector 123. The control calculator 72c calculates the deviation and controls the opening and closing of the steam ejector 112 based on the control amount.

With this control, when the current of the DC output 100 is increased, the amount of hydrogen supplied to the reformer 113 is increased and the amount of steam is also increased to maintain the mixing ratio of both.

In the burner air flow rate control unit 73, the DC current detected by the DC current detector 102 is transferred to the function unit 73a.
Is input to and converted into a burner air flow rate. The deviation between the target value and the detection value detected by the burner air flow rate detector 125 is calculated by the deviation calculator 73b. This deviation is control-calculated by the control calculator 73c, and the control amount of the burner air control valve 116 is calculated. The burner air control valve 116 is opened / closed by this control amount, and the burner air flow rate is controlled. With this control, when the current of the DC output 100 increases, the burner air flow rate increases as the DC output 100 increases.

In the process air flow rate control section 74, the DC current detected by the DC current detector 102 is transferred to the function section 74.
It is input to a and converted to the target value of the process air control valve opening. This target value and process air control valve opening detector 1
The deviation from the detection amount detected by 26 is the deviation calculation unit 74.
Calculated from b. This deviation is control-calculated by the control calculator 74c to calculate the control amount, and the process air control valve 1
Opening / closing control of 17 is performed. DC output 1 by this control
The air flow rate is increased in accordance with the increase of 00.

In the battery cooling water temperature control section 75, the DC current detected by the DC current detector 102 is transferred to the function section 75a.
And is converted into a target value of the temperature of the battery cooling water.
The deviation between the target value and the detection amount detected by the battery cooling water temperature detector 127 is calculated by the deviation calculator 75b.

The control calculation unit 75c1 calculates the control amount for the battery cooling water temperature control valve 120 from the deviation,
Open / close control is performed. Further, in the control calculation unit 75c2,
A control amount for the battery cooling water heater 118 is calculated from the deviation, and ON / OFF control is performed. The temperature of the battery cooling water is adjusted by the ON / OFF control of the battery cooling water heater 118 and the opening / closing control of the battery cooling water temperature control valve 120. As a result, if the DC output 100 increases and the battery cooling water temperature rises, the battery cooling water is controlled to fall.

The operation of the process control device 14 shown in FIG. 17 described above will be explained with reference to the system diagram of the plant shown in FIG. 16. The fuel flow control unit 71 and the steam ejector control unit 72 cause the fuel control valve 110 to operate. The steam ejector 112 is controlled, and fuel such as natural gas is supplied to the fuel control valve 11
The flow rate is controlled by 0, and this fuel is steam separator 11
The steam ejected from No. 1 is mixed with the steam ejector 112, enters the reformer 113, and is heated under the catalyst to be a reformed fuel having a high hydrogen content.

After the carbon monoxide is removed by the transformer 114, the reformed fuel flows into the fuel electrode 12A of the fuel cell 12 and is partially consumed as electric energy. The remainder of the reformed fuel is used as the heating fuel gas for the reformer 113, and the burner air flow rate control unit 73 is used in the combustor 115.
The burner air control valve 116 is combusted together with the air whose flow rate is controlled by the control according to (4).

At the air electrode 12B of the fuel cell 12, the process air control valve 11 is controlled by the process air flow rate control unit 74.
7 is opened and closed, the flow rate is controlled, and air is supplied. In the fuel cell 12, a DC output 1 which is electric energy is generated by a catalytic reaction between oxygen in the air supplied to the air electrode 12B and hydrogen of the reformed fuel supplied to the fuel electrode 12A.
00 is generated. At this time, the fuel electrode 12A becomes the negative electrode and the air electrode 12B becomes the positive electrode.

Further, in order to keep the temperature of the battery constant and to supply the steam to the steam ejector 112 described above,
The battery cooling water temperature control unit 75 adjusts the temperature of the battery cooling water by the opening degree of the battery cooling water temperature control valve 120 which is a bypass valve to the battery cooling water heater 118 and the heat exchanger 119.

These controls are changed by the amount of hydrogen in the reformed fuel supplied to the fuel electrode 12A of the fuel cell 12 and the amount of oxygen in the air supplied to the air electrode 12B according to the increase / decrease in the DC output 100.

In this case, in order to adjust the amount of hydrogen in the reformed fuel, the fuel flow rate controlled by the fuel control valve 110 according to the DC output 100 and the mixture of steam and fuel controlled by the steam ejector 112. In order to control the ratio and the steam supplied to the steam ejector 112, the battery cooling water temperature control valve 120 and the battery cooling water heater 11 are provided.
8 controls the temperature of the battery cooling water and the amount of air supplied to the combustor for heating the reformer 113, which is controlled by the burner air control valve 116.

On the other hand, the amount of oxygen in the air supplied to the air electrode is controlled by the process air control valve 117 according to the DC output 100. By obtaining these control target values from the above-mentioned direct current, the direct current output 100 can be made to follow the changes in the direct current that occur when the alternating current output 101 changes.

[0161]

As described above, according to the invention of claim 1, in each of a plurality of plants in parallel operation, control is performed so that an alternating current based on the PWM pattern of the same shape is output from the orthogonal transformer. Then, each plant shares the load in accordance with the power demand of the specific load. Since the PWM patterns can have the same shape, the active power, the reactive power, and the output voltage are the same in each plant, and thus it is possible to prevent cross current during parallel operation. Further, even if one plant in parallel operation stops due to a failure or the like, the load sharing of each of the remaining plants can be changed, and the number of plants to be operated later can be increased during parallel operation. Therefore, it is not necessary to manufacture one dedicated plant for a specific load, and a plurality of general-purpose mass-produced plants can be used to meet the power demand and economical operation can be performed.

According to the second aspect of the present invention, when the master plant fails and stops during parallel operation, the next master plant is immediately determined from the priority index of each plant, and smooth parallel operation is achieved. When a plant that is in operation stops due to an increase or decrease in the power demand of a specific load or a failure during operation, and when the plant that is stopped resumes operation,
The load sharing amount is calculated, and the electric power of each plant is output based on the calculated load sharing amount. Therefore, it is possible to reliably and reliably follow the power demand of the specific load during parallel operation.

According to the third aspect of the present invention, the synchronization signal generated in the master plant is transmitted to the slave plant via the synchronization signal transmission line, bypassed in the case of an abnormal or stopped plant, and returned to the normal state on the way. When the operation is restarted, the synchronization signal is taken into the slave plant without bypassing, so even if the plant becomes abnormal, stops, or restarts during parallel operation, it does not affect the specific load. Each plant can supply synchronized electric power without supplying.

According to the fourth aspect of the invention, the active power phase control section outputs the phase control signal so that the active power amount synchronized with the synchronizing signal and output from the quadrature converter becomes the load sharing amount, and the voltage control is performed. Part outputs a voltage signal so that the voltage from the AC conversion generation becomes the target value of the master plant, and the reactive power control part causes the reactive power output from the orthogonal converter to become the reactive power sharing amount. The DC output voltage of is controlled. Further, a PWM waveform is generated from the phase control signal and the voltage signal. As a result, the PWM waves of each plant have the same pattern, a cross current does not occur between the plants, and electric power of a waveform with less distortion can be supplied to a specific load.

According to the fifth aspect of the present invention, each process amount is tracked by increasing or decreasing each process amount in the plant in advance in accordance with the increase or decrease of the DC output current output from the DC power generation unit. As a result, in parallel operation, the load sharing is likely to change, the AC output from the orthogonal converter changes, and the DC output current of the DC power generation unit fluctuates, but the process amounts change accordingly. Therefore, the load on the fuel cell is reduced and the entire plant is always stable.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a parallel operation system of a fuel cell power plant showing a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a state transition of the load sharing control device provided in FIG.

FIG. 3 is a first diagram showing a processing procedure of the load sharing control device of FIG.
It is a flowchart of.

FIG. 4 is a second diagram showing a processing procedure of the load sharing control device of FIG.
It is a flowchart of.

5 is an explanatory diagram showing a memory content provided in the load sharing control device of FIG. 1. FIG.

FIG. 6 is an explanatory diagram showing a synchronization signal generated by the electric control device of FIG. 1.

FIG. 7 is a third flowchart showing the processing procedure of the load sharing control device of FIG.
It is a flowchart of.

FIG. 8 is a configuration diagram of a load sharing control device showing a second embodiment of the present invention.

9 is a flowchart showing a processing procedure of a calculation unit and a master plant determination unit in FIG.

FIG. 10 is an explanatory diagram showing transition of the priority number of FIG.

FIG. 11 is a configuration diagram of a synchronization signal switching device showing a third embodiment of the present invention.

12 is a configuration diagram of the electric control device shown in FIG. 11. FIG.

FIG. 13 is a configuration diagram of an electric control device provided in a parallel operation device of a fuel cell power plant showing a fourth embodiment of the present invention.

FIG. 14 is a control block diagram of a parallel operation system of the fuel cell power generation plant shown in FIG.

FIG. 15 is a configuration diagram of a parallel operating system for a fuel cell power plant showing a fifth embodiment of the present invention.

16 is a system diagram of a fuel cell plant to which the parallel operating system of the fuel cell power plant of FIG. 15 is applied.

17 is a configuration diagram showing the process control apparatus of FIG.

FIG. 18 is a configuration diagram of a control device for a fuel cell power plant showing a conventional example.

FIG. 19 is a control block diagram showing the electric control device of FIG. 18.

FIG. 20 is an explanatory diagram showing an example of a PWM wave output to the orthogonal converter of FIG. 18.

21 is a control block diagram of the electric control device shown in FIG. 18. FIG.

[Explanation of symbols]

1 Fuel cell plant 2 DC generator 3 control device 4 AC output section 6 load 7 data transmission path 8 Sync signal transmission line 10 Orthogonal transformer 11 DC booster 12 batteries 13 Electric control device 14 Process control equipment 15 Load sharing control device 16 Sync signal switching device 20 common memory 31 Calculation Department 32 Master plant decision unit 33 Load sharing amount determination unit 44 Electric control device monitor 45 Synchronous signal processing device 71 Fuel flow controller 72 Steam ejector control unit 73 Burner Air flow controller 74 Process air flow controller 75 Battery cooling water temperature controller 81 Active power control means 83 Phase control means 84 Reactive power control means 85 voltage control means 86 Booster voltage control means 89% F calculation means 92 Reactive power control means 102 DC current detector 103 AC output detector 110 Fuel control valve 112 Steam ejector 116 burner air control valve 117 Process air control valve 120 Battery cooling water temperature control valve 122 Fuel flow rate detector 123 Steam ejector opening detector 124 Reformer temperature detector 125 burner air flow detector 126 Position detector 127 Battery cooling water temperature detector

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Takahiro Mori 1st Toshiba Town, Fuchu-shi, Tokyo Tokyo Toshiba Fuchu Co., Ltd. (72) Inventor Tokuju Sasan 1st Toshiba Town, Fuchu, Tokyo Toshiba Fuchu Corporation In-plant (72) Inventor Haruo Matsumuro 1 Toshiba Town, Fuchu-shi, Tokyo Toshiba Fuchu Co., Ltd. In-plant (56) Reference JP-A-60-37673 (JP, A) JP-A-61-254026 (JP, A) ) JP-A-62-268323 (JP, A) JP-A-6-338341 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01M 8/00 H01M 8/04 H02J 3 / 38 H02J 1/12

Claims (5)

(57) [Claims] 1. A power supply system in which a plurality of fuel cell plants for a specific load are connected in parallel to form a power supply system,
Each plant has a DC power generation unit that generates a DC voltage by a fuel cell, an AC output unit that has a quadrature converter that boosts the DC voltage generated by this DC power generation unit and converts DC to AC, and the DC power generation unit And a process control device for controlling each process amount, and a slave master plant that determines one master plant leading among the plurality of plants according to the operation stop state of the plant and the rest as slaves to the master plant. Along with, the load sharing control device that determines the load burden amount of each plant from the power demand of the specific load and the number of operating plants, and the AC output of the master plant to the specific load and the AC output of the slave plant. Synchronize with AC output of own plant when own plant is master plant to synchronize Signal is output while the own plant is a slave plant, the synchronous signal switching device that takes in the synchronous signal of the master plant, and the active power amount and the reactive power output from the orthogonal converter are the respective load sharings. Following the quantity, the voltage output from the quadrature converter becomes the target value of the master plant, and each plant has the same AC waveform output from the quadrature converter synchronized with the master plant synchronization signal to the specific load. A parallel operation device for a fuel cell power plant, comprising: an electric control device that generates a PWM signal so as to perform the above operation; and a common memory that captures the operation condition of each plant and stores the operation condition of all plants. 2. The load sharing control device fetches the operating or shutdown status of each plant from the common memory, and indicates which plant is given priority as the master plant according to a predetermined rule by an index of priority. A calculation unit that calculates the priority index of the own plant and saves it in the common memory, and inputs the priority index of each plant from the common memory, and the own plant is mastered from the magnitude relationship of these priority indices. A master plant determination unit that determines a plant or a slave plant and saves it in the common memory, and a load sharing of each plant according to a predetermined calculation from the required amount of the specific load and the number of plant operating units taken from the common memory A fuel cell generator according to claim 1, further comprising: a load sharing amount determining unit that calculates the amount and stores the amount in the common memory. Parallel operation equipment for electric power plants. 3. The electric control device refers to the common memory to output a synchronization signal when the own plant is a master plant, while once taking in a synchronization signal from a master plant of another plant when the own plant is a slave plant. A synchronization signal processing device for bypass output, and an electric controller monitoring device that outputs a bypass signal by which the synchronization signal bypasses the synchronization signal processing device when the own plant is stopped or abnormal, the synchronization signal switching device, A synchronizing signal having an inlet side for inputting the synchronizing signal and an outlet side for outputting the synchronizing signal and forming a closed loop so that the inlet side and the outlet side of each plant are mutually connected and the synchronizing signal is transmitted to each plant. When the bypass signal is input while the synchronization signal from the synchronization signal processing device is taken in and output from the transmission line, Parallel operation of a fuel cell power plant according to claim 1 or claim 2, wherein the provision of the synchronizing signal switching means for switching a signal to be bypassed. 4. The electric control device fetches various data from the common memory, fetches a synchronizing signal from the synchronizing signal processing device when the own plant is a master plant, or activates the synchronizing signal switching device when the own plant is a slave plant. A synchronization signal input unit for taking in a synchronization signal via the active power phase control for synchronizing with the synchronization signal and outputting a phase control signal so that the amount of active power output from the orthogonal transformer becomes the load sharing amount. Unit, a voltage control unit that outputs a voltage signal so that the voltage output from the orthogonal transformer has a voltage target value predetermined by the master plant, and the reactive power output from the orthogonal transformer is the reactive power. A reactive power control unit for increasing or decreasing the DC output voltage of a DC boosting unit provided in the AC output unit so as to provide a power burden; and the active power phase control unit. 4. The PWM wave generator for inputting the phase control signal according to claim 1 and the voltage signal from the voltage controller to generate a PWM waveform and output the PWM waveform to the orthogonal converter. A parallel operation apparatus of any one of the fuel cell power generation plants described. 5. The process control device controls the fuel control valve according to an increase / decrease in the DC output current, using the DC output current from the DC power generation unit as a target value by a predetermined function, and controls the fuel control valve to perform the reforming fuel injection. A fuel flow rate control unit for increasing / decreasing the hydrogen, a steam ejector control unit for increasing / decreasing the mixing ratio of the steam amount and the hydrogen amount according to the increase / decrease in the DC output current and the increase / decrease in the reformed hydrogen, and the increase / decrease in the DC output current. A burner air flow control unit that controls the burner air control valve to increase or decrease the amount of air to the burner, and a process air control valve that controls the process air control valve to increase or decrease the DC output current. A process air flow rate control unit for controlling the battery cooling water heater and a battery cooling water temperature control valve for controlling the battery cooling water temperature control valve according to the increase or decrease of the DC output current. Parallel operation device of any of the fuel cell power plant of claim 1 to claim 4 wherein.