JPH08317659A - Power-supply apparatus making use of fuel cell - Google Patents

Abstract

PURPOSE: To obtain a power-supply apparatus, making use of a fuel cell, which can be started in a short time as far as possible while the damage of an orthogonal transformation means is being prevented when an overcurrent protective device is not installed irrespective of the kind and the capacity of an external load device or while the operation of the overcurrent protective device is being suppressed as far as possible when the overcurrent protective device is installed. CONSTITUTION: An allowable-current-value setting means 101 which sets an allowable current value so as to be increased gradually from a set minimum value is installed in a process in which a control means 100 increases an output voltage gradually on the basis of an output command. Then, the control means 100 is constituted in such a way that it detects the output current of an orthogonal transformation means 1 in a process in which the output voltage is increased gradually on the basis of the output command and that it controls the orthogonal transformation means 1 so as to control the output voltage or an output frequency or both the output voltage and the output frequency in such a way that, when the output current becomes larger than the allowable current value, the output current becomes the allowable current value or lower.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an opening / closing circuit for connecting an external load device to a quadrature conversion means for converting output DC power of a fuel cell into AC power, and for opening / closing a connection between the quadrature conversion means and the external load device. Means is provided, and based on an output command for outputting the output AC power of the orthogonal transformation means to the external load device, the orthogonal transformation means is controlled so as to reduce the output voltage of the orthogonal transformation means to a set minimum value. After that, the present invention relates to a power supply device using a fuel cell provided with a control means for switching the opening / closing means to a closed state and then controlling the orthogonal transformation means so as to gradually increase the output voltage.

[0002]

2. Description of the Related Art A power supply device using such a fuel cell (hereinafter referred to as
In some cases, the power supply device may be simply abbreviated), and when the switching means is switched to the closed state while some voltage is being output from the orthogonal transformation means, the output current of the orthogonal transformation means considerably exceeds the rated current at the time of switching. There is a risk that the orthogonal transformation means may be damaged because the current exceeds the above, in other words, a so-called inrush current flows. Therefore, in general, when the output current exceeds a set value, an overcurrent protection device that stops the operation of the power supply device by setting the output voltage to zero is provided to prevent damage to the orthogonal transformation means. However, even if the overcurrent protection device is provided, if the switching means is switched to the closed state while the rated voltage is being output from the orthogonal transformation means, the output current becomes large and the overcurrent protection device operates. Since the power supply device stops, the power supply device cannot be started up smoothly. Therefore, based on the output command for outputting the output AC power of the orthogonal transformation means to the external load device, the control means controls the orthogonal transformation means so as to reduce the output voltage of the orthogonal transformation means to the set minimum value, and then opens and closes. The means is switched to the closed state, and then the orthogonal transformation means is controlled so as to gradually increase the output voltage. Then, the output current is made as small as possible to suppress the operation of the overcurrent protection device as much as possible.

[0003]

However, even when the output voltage is gradually increased at startup, the output current becomes large and the overcurrent protection device operates depending on the type (especially, electric motor) and capacity of the external load device. There was a case to do. Therefore, it is possible to set the gradual increase rate of the output voltage to an extremely small value in order to avoid the operation of the overcurrent protection device regardless of the type and capacity of the external load device. It will take a long time until
It takes a long time to start, so it is not practical. On the other hand, if you set the gradual increase rate of the output voltage so that it can be started in a practical time, depending on the type and capacity of the external load device, the overcurrent protection device may operate and it may not start smoothly. There was a problem that there is. By the way, if the overcurrent protection device is not provided, it is assumed that the gradual increase rate of the output voltage is set to be extremely small to suppress the output current to prevent the orthogonal transformation means from being damaged. It is not practical because it takes a long time to start.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a power supply device using a fuel cell in the case where an overcurrent protection device is not provided regardless of the type and capacity of an external load device. To prevent damage to the orthogonal transformation means, or, if an overcurrent protection device is provided, to suppress the operation of the overcurrent protection device as much as possible, while enabling activation in the shortest possible time. Is to

[0005]

A first characteristic configuration of a power supply device using a fuel cell according to the present invention is such that an allowable current value is gradually increased from a set minimum value in a process in which the control means gradually increases the output voltage. The allowable current value setting means for setting is set, and the control means detects the output current of the orthogonal transformation means in the process of gradually increasing the output voltage, and the output current becomes larger than the allowable current value. , The quadrature conversion means for adjusting the output voltage, the output frequency of the quadrature conversion means, or both the output voltage and the output frequency so that the output current becomes equal to or less than the allowable current value. It is configured to control.

In a second characteristic configuration, the control means controls the quadrature transformation means based on the output command so as to reduce the output frequency of the quadrature transformation means to a set minimum value, and controls the output voltage. In the process of gradually increasing, the orthogonal transforming means is controlled so as to gradually increase the output frequency.

In a third characteristic configuration, the control means causes the output current to approach the allowable current value when the output current becomes smaller than the allowable current value in the process of gradually increasing the output voltage. , The output voltage, the output frequency, or both of the output voltage and the output frequency are controlled to control the orthogonal transformation means.

A fourth characteristic configuration is a power supply state in which the external load device is connected to a commercial power source and electric power is being supplied from the commercial power source to the external load device, and the external load device from the commercial power source. Detection means is provided for detecting a cutoff state in which the supply of electric power to the power supply is cut off, and the control means cuts off the cutoff state during the interconnection operation in which the detection means detects the power supply state based on the detection information of the detection means. When the state is detected, the opening / closing means is opened, and then the control based on the output command is executed.

[0009]

The operation of the first characteristic configuration is as follows. When the output command is given, the control means controls the orthogonal transformation means so as to reduce the output voltage to the set minimum value, then switches the opening / closing means to the closed state, and then performs the orthogonal transformation so as to gradually increase the output voltage. Control means. Further, the permissible current value setting means sets the permissible current value to gradually increase from the set minimum value in the process of the control means gradually increasing the output voltage, and the control means outputs the output voltage in the process of gradually increasing the output voltage. When the current is detected and the output current becomes larger than the allowable current value, the output voltage, the output frequency, or both the output voltage and the output frequency are decreased so that the output current becomes the allowable current value or less. The orthogonal transform means is controlled to adjust. Therefore, the output voltage is gradually increased from the set minimum value, and the output current is controlled and activated so as not to exceed the gradually set allowable current value.

When the output current becomes larger than the allowable current value, the output current can be made equal to or lower than the allowable current value by adjusting only the output voltage or the output frequency. However, if both the output voltage and the output frequency are adjusted to be reduced, the output current can be reduced to the allowable current value or less quickly, in other words, with higher sensitivity. Further, in the case of an electric motor, the lower the frequency of the electric power supplied at the time of starting, the smaller the starting current. Therefore, when the external load device is an electric motor, even if only the output frequency is adjusted to decrease when the output current becomes larger than the allowable current value,
The output current can be kept below the allowable current value with a relatively high sensitivity.

The operation of the second characteristic configuration is as follows. The control means controls the orthogonal transformation means so as to reduce the output frequency to a set minimum value based on the output command, and controls the orthogonal transformation means so as to gradually increase the output frequency in the process of gradually increasing the output voltage. . Therefore, the output voltage and output frequency gradually increase from their respective set minimum values,
In addition, the output current is controlled and activated so as not to exceed the allowable current value that is set to be gradually increased.

The operation of the third characteristic structure is as follows. When the output current becomes smaller than the allowable current value in the process of gradually increasing the output voltage, the control means outputs the output voltage or the output frequency, or the output voltage and the output frequency so that the output current approaches the allowable current value. The orthogonal transform means is controlled so as to increase and adjust both of the above. That is,
Even if the external load capacity is small and the output current at startup is smaller than the allowable current value, the output voltage or output frequency or the
Both the output voltage and the output frequency are adjusted up. Therefore, the output current is controlled and started so as to be maintained in the vicinity of the allowable current value that is set to be gradually increased.

When the output current becomes smaller than the allowable current value, the output current can be brought close to the allowable current value by adjusting only the output voltage or the output frequency. By increasing and adjusting both the output voltage and the output frequency, the output current can be brought closer to the allowable current value more quickly, in other words, with higher sensitivity. In the case of an electric motor, the higher the frequency of the electric power supplied at the time of starting, the larger the starting current. Therefore, when the external load device is an electric motor, even if only the output frequency is increased and adjusted when the output current becomes smaller than the allowable current value,
The output current can be brought close to the allowable current value with relatively high sensitivity.

The operation of the fourth characteristic structure is as follows. During the interconnection operation in which power is supplied to the external load device by the interconnection of the power supply device using the fuel cell and the commercial power supply, the detection means is in the cutoff state in which the power supply from the commercial power supply to the external load device is cut off. When the shutoff state is detected, the control means once switches the opening / closing means to the open state, and then executes the control based on the output command as described above. Therefore, even if the supply of power from the commercial power source to the external load device is cut off during the interconnection operation, the output current does not exceed the allowable current value that is gradually set, or the output current is gradually increased. It is possible to switch to a state in which the power supply device using the fuel cell alone supplies power to the external load device by being controlled so as to be maintained near the value.

[0015]

According to the first characteristic configuration, even if the gradual increase rate of the output voltage is set to a considerably large value, the output current is controlled so as not to exceed the allowable current value. As a result, even if the overcurrent protection device is not provided, the orthogonal transformation means can be started in a short time while being prevented from being damaged. Further, when the overcurrent protection device is provided, the operation of the overcurrent protection device can be suppressed as much as possible, and the overcurrent protection device can be activated in a short time.

When the output current becomes larger than the allowable current value, the output voltage is decreased or adjusted so that the output current is equal to or less than the allowable current value, or the output frequency is decreased. In some cases, both the output voltage and the output frequency may be adjusted down. Of these, when both the output voltage and the output frequency are adjusted to be reduced, the activation can be performed in the shortest time. Further, when the output voltage is adjusted down, the time required for start-up may take a little longer than when both the output voltage and the output frequency are adjusted down, but the configuration of the control means can be simplified. The cost for carrying out can be reduced. Further, when the output frequency is adjusted to be reduced, if the external load device is an electric motor in particular, it is possible to reduce the cost for implementing the present invention while suppressing the increase in the time required for startup as much as possible. You can

According to the second characteristic structure, the output current can be further reduced and the gradual increase rate of the output voltage can be set to be larger than that of the first characteristic structure. It is possible to start up in a shorter time than with the first feature configuration.

According to the third characteristic configuration, the output current is controlled so as to be maintained near the allowable current value regardless of the capacity of the external load device. In addition to the effect obtained, there is an effect that the external load device can be activated in a shorter time when the capacity of the external load device is small.

In order to bring the output current close to the allowable current value when the output current becomes smaller than the allowable current value, the output voltage is increased or adjusted, or the output frequency is increased or adjusted. Both output voltage and output frequency may be adjusted up. Among these, when increasing and adjusting both the output voltage and the output frequency, the activation can be performed in the shortest time. In addition, when the output voltage is increased and adjusted, the time required for startup may be slightly longer than when both the output voltage and the output frequency are increased and adjusted, but the configuration of the control means can be simplified. The cost for carrying out can be reduced. In addition, when the output frequency is increased and adjusted, if the external load device is an electric motor in particular, it is possible to reduce the cost for implementing the present invention while suppressing the increase in the time required for startup as much as possible. You can

According to the fourth characteristic configuration, when power is supplied to the external load device by the interconnection of the power source device using the fuel cell and the commercial power source, the power supply from the commercial power source to the external load device is cut off. Thus, even when the power supply device using the fuel cell alone switches to the state of supplying power to the external load device, the same effects as those obtained by the first, second, or third characteristic configuration can be obtained. .

[0021]

Embodiments of the present invention will be described below with reference to the drawings. First, an overall configuration of a power supply device using a fuel cell (hereinafter, may be simply referred to as a power supply device) will be described with reference to FIG. The power supply device S controls a fuel cell power generation unit G that generates direct current power, an inverter 1 as an orthogonal conversion unit that converts the output direct current power of the fuel cell power generation unit G into alternating current power, and various controls of the power supply device S. Control device C
It has.

An external load device 5 and an auxiliary device A of a fuel cell power generation section G, which will be described later, are connected to the output line 2 of the inverter 1, and the external load device 5 and the auxiliary device A are connected to the output line 3 of the commercial power source 6. Are connected. The output line 2 of the inverter 1 is provided with an opening / closing device S1 as an opening / closing means for opening / closing the connection between the inverter 1 and the external load device 5, and an opening / closing device S2 for opening / closing the connection between the inverter 1 and the auxiliary machine A. is there. Further, in the output line 3 of the commercial power supply 6, a switchgear S3 that opens and closes the connection between the commercial power supply 6 and the external load device 5, and a switchgear S that opens and closes the connection between the commercial power supply 6 and the auxiliary equipment A.
4 is provided. Further, a power failure detection device 4 for detecting a power failure of the commercial power supply 6 is provided. That is, by closing the switchgear S1 and the switchgear S3, power is supplied to the external load device 5 by the interconnection of the power supply S according to the present invention and the commercial power supply 6. is there.

Next, based on FIG. 3, the fuel cell power generation unit G
Will be added. The fuel cell power generation unit G includes a desulfurization device 11 that desulfurizes the supplied raw fuel gas (hydrocarbon-based gas such as natural gas), and a steam separation device 12 that generates water vapor.
And an ejector 13 that mixes and ejects the desulfurization raw fuel gas supplied from the desulfurization device 11 and the steam supplied from the steam separation device 12, and the desulfurization raw fuel gas and steam supplied from the ejector 13 are modified. Reforming device 14 for producing a reformed gas containing hydrogen gas and carbon monoxide gas as main components by a quality reaction, and carbon monoxide gas and steam in the reformed gas supplied from reforming device 14 A conversion device 15 for reacting and converting to carbon dioxide gas to generate a fuel gas containing hydrogen gas and carbon dioxide gas as main components; a blower 16;
A phosphoric acid electrolyte fuel cell 17 is provided, which generates direct current power by an electrochemical reaction between hydrogen gas in the fuel gas supplied from the shift converter 15 and oxygen gas in the air supplied from the blower 16. In addition, the cooling water is separated into a steam separation device 12
A pump 18 that circulates the fuel from the fuel cell 17 to the fuel cell 17 is provided. The blower 16 and the pump 18 correspond to the auxiliary machine A.

Next, the control device C will be described.
First, the control configuration of the control device C will be described with reference to FIG. The control device C includes a voltage control unit C1 that creates and outputs a voltage control signal v, a frequency control unit C2 that creates and outputs a frequency control signal f, and a voltage control unit C1 that outputs a voltage control signal. A correction unit C3 that operates to correct the signal v to create and output a correction voltage control signal v ′, and to correct the frequency control signal f created by the frequency control unit C2; An inverter drive unit 21 that creates and outputs an output control signal vf for controlling the output voltage V and the output frequency F of the inverter 1 based on the signal v ′ and the frequency control signal f;
Based on the operation / stop control of each of the frequency control unit C2 and the correction unit C3, and the information on the switching state of the switching device S3 or the detection information of the power failure detection device 4, the switching devices S1, S2.
The operation control unit 22 executes the opening / closing control of S4. Then, the inverter drive unit 21 sends an output control signal vf to a driver circuit (not shown) of the inverter 1 to control the output voltage V and the output frequency F of the inverter 1.

Next, the voltage controller C1 will be described. The voltage controller C1 includes a switch 23 and a reference voltage E ₁
A first reference voltage generating circuit 24 for generating a reference voltage E ₁
And a comparison voltage corresponding to the output voltage V of the inverter 1 (for example, a voltage converted so as to correspond to the output voltage V of the inverter 1) V ₁ (a positive voltage). I am doing it. The switch 23 can be composed of, for example, an FET. The first reference voltage generating circuit 24, as shown in FIG.
When the switch 3 is on, the reference voltage is 0 V, and when the switch 23 is off, the voltage gradually decreases during a predetermined time (hereinafter, referred to as a voltage soft start period), and becomes constant when the steady state is reached after the voltage soft start period elapses. It is configured to generate E ₁ .

When the operation of the inverter 1 is stopped, the operation control unit 22 turns on the switch 23, so that the comparison voltage V
₁ and the reference voltage E ₁ are 0V, and the voltage control signal v output from the voltage control unit C1 is 0V. When the operation control unit 22 turns on the switch 23 and the inverter 1 is activated, the absolute value of each of the comparison voltage V ₁ and the reference voltage E ₁ becomes larger at the reference voltage E ₁ during the voltage soft start period. , The voltage control signal v becomes a negative voltage signal. The correction voltage control signal v ′ is equal to the voltage control signal v when the correction unit C3 does not perform the correction operation, and the inverter drive unit 21 increases the output voltage V based on the correction voltage control signal v ′. Therefore, the output control signal vf is created.
Therefore, the output voltage V of the inverter 1 gradually increases from 0 V (corresponding to the set minimum value) to the rated voltage during the voltage soft start period. The state in which the inverter 1 is controlled so that the output voltage V gradually increases from 0 V (corresponding to the set minimum value) to the rated voltage at the time of startup is called voltage soft start control. When the voltage soft start period elapses and the steady state is reached, the comparison voltage V ₁ and the reference voltage E ₁ are set so that the output voltage V is maintained at the rated voltage.
Controlled based on.

Next, the frequency controller C2 will be described. Frequency controller C2, a switch 26, for generating a third reference voltage generating circuit 27 for generating a reference voltage E _3, the frequency control signal f having a frequency corresponding to the correction reference voltage E ₃ 'input V / It is composed of an F converter 28. The switch 26 can be configured by a relay, for example. As shown in FIG. 4C, the third reference voltage generating circuit 27 outputs E ₃ a when the switch 26 is on.
At V, when the switch 26 is turned off, the voltage gradually increases during a predetermined time (hereinafter referred to as a frequency soft start period), and when the frequency soft start period elapses and becomes a steady state, the reference voltage E ₃ becomes constant at E ₃ bV. Is configured to generate.

When the operation control unit 22 turns on the switch 26 and the inverter 1 is started, V / F is maintained during the frequency soft start period when the correction unit C3 does not make a correction.
Is the corrected reference voltage E ₃ 'is input to the converter 28 equal to the reference voltage E _3, since the gradual increase from E ₃ aV to E ₃ bV, frequency of the frequency control signal f output from the V / F converter 28 is gradually increased To do. Therefore, based on such a frequency control signal f, the inverter drive unit 21
Since the output control signal vf is generated, the output frequency F of the inverter 1 gradually increases from the set minimum value to the rated frequency during the frequency soft start period. The state in which the inverter 1 is controlled so that the output frequency F gradually increases from the set minimum value to the rated frequency at the time of startup is called frequency soft start control.

Next, the correction section C3 will be described.
Corrector C3 includes a switch 29, reference voltage second reference voltage generating circuit 30 for generating the E _2, reference voltage E ₂ and the output current comparison voltage corresponding to I of the inverter 1 (e.g., the output current of the inverter 1 flowing a I to a resistor and a coil for detecting a voltage) is compared with V _2, and, when the comparative voltage V ₂ is greater than the reference voltage E _2, the correction current corresponding to a difference between them a second determination circuit 31 that outputs i, a first correction circuit 32 that corrects the voltage control signal v based on the correction current i and outputs a correction voltage control signal v ′, and a first correction circuit 32 that outputs the correction current i based on the correction current i. To correct the reference voltage E ₃ to correct the reference voltage E
The second correction circuit 33 outputs ₃ '.
The switch 29 can be configured with a relay, for example.

The second reference voltage generating circuit 30 has a voltage of 0 V when the switch 29 is on, as shown in FIG.
At the output current I of the inverter 1 (corresponding to 0 A), when the switch 29 is turned off, the voltage gradually decreases during a predetermined time (hereinafter referred to as a current soft start period), and the voltage soft start period elapses to reach a steady state. Then, the reference voltage E ₂ that is constant (corresponding to the rated current of the inverter 1) is generated. Therefore, the second discrimination circuit 3
1 indicates that when the comparison voltage V ₂ is higher than the reference voltage E ₂ ,
That is, when the output current I of the inverter 1 is larger than the current value (hereinafter referred to as the allowable current value) Is corresponding to the reference voltage E ₂ , the correction current i corresponding to the difference between them is output. .

The first correction circuit 32 corrects the voltage control signal v based on the correction current i so that the relationship between the output voltage V and the output current I of the inverter 1 is as shown in FIG. . That is, as the output current I becomes larger than the permissible current value Is, the output voltage V is greatly reduced.
The voltage control signal v is corrected based on the correction current i.
In addition, the second correction circuit 33 performs correction based on the correction current i so that the reference voltage E ₃ is greatly reduced as the correction current i increases.

That is, when the operation of the inverter 1 is stopped, the operation controller 22 turns on the switch 29, so that the allowable current value Is is 0 A, and the operation controller 22 causes the switch 2 to operate.
When 9 is turned on and the inverter 1 is started, the permissible current value Is gradually increases from 0 A to the rated current during the current soft start period. Then, when the output current I becomes larger than the allowable current value Is during the current soft start period, the output voltage V and the output frequency F are lowered so that the output current I becomes equal to or smaller than the allowable current value Is. Control. still,
Thus, at the time of start-up, the allowable current value Is is gradually increased, and when the output current I becomes larger than the allowable current value Is, the output voltage V and the output frequency F are set so that the output current I becomes the allowable current value Is or less. The control for decreasing the current is called current soft start control. Further, in the steady state, when the output current I becomes larger than the allowable current value Is (equal to the rated current), the output voltage V is decreased based on the relationship shown in FIG. 5, and the output current I becomes the rated current. 1.5 times,
The output voltage V is reduced to 0V to protect the inverter 1.

As described above, when the inverter 1 is started,
When voltage soft start control, frequency soft start control and current soft start control are executed, the inverter 1
The output voltage V, the output frequency F, and the permissible current value Is are gradually increased from the set minimum value to the rated value. FIG. 6 shows an example of the voltage soft start control, the frequency soft start control, and the current soft start control. 6 shows that the output current I does not become larger than the allowable current value Is during the execution of the voltage soft start control and the frequency soft start control, and the correction unit C3 does not perform the correction operation. The state of the gradual increase of the voltage V and the output frequency F is shown. Therefore, when the correction unit C3 corrects, the actual output voltage V and the output frequency F become lower than those in the state shown in FIG.
Further, during the current soft start control, when the correction section C3 is constantly operated for correction, the output current I is consequently substantially in the same state as the allowable current value Is shown in FIG. It will change gradually.

Next, the control configuration of the power supply device S executed by the control device C will be described with reference to FIG. The control device C (operation control unit 22) includes switching devices S1, S
2, S3, S4, and the power failure detection device 4 are connected, and the opening / closing control of each of the switching devices S1, S2, S4 is performed based on the information on the switching status of the switching device S3 and the detection information of each power failure detection device 4. It is configured as follows.

In the start-up operation in which the fuel cell 17 is brought into a state capable of generating electric power, the opening / closing devices S1 and S2 are switched to the open state, and the opening / closing device S4 is switched to the closed state. Therefore, the auxiliary machine A is supplied with power from the commercial power supply 6.

When the start-up operation is completed and the start-up operation end command is given to the control device C, the switchgear S2 is switched to the closed state, and the switchgear S4 is switched to the open state. , 26, 29 are turned off to start the inverter 1. Therefore, the inverter 1 is started based on the voltage soft start control, the frequency soft start control, and the current soft start control. As a result, the DC power generated by the fuel cell 17 is converted into AC power by the inverter 1, and the AC power is supplied to the auxiliary machine A, so that a so-called self-sustaining operation is executed. The start-up operation end command is configured to be provided, for example, when a temperature sensor (not shown) that detects the temperature of the fuel cell 17 is provided and the detected temperature reaches the set temperature.

During the above-described independent operation, the inverter 1
When an output command for outputting the output AC power of the above to the external load device 5 is given by a switch (not shown) or the like, after turning on the switches 23, 26, 29 and stopping the inverter 1 (that is, the inverter After decreasing the output voltage V and the output frequency F of 1 to the respective set minimum values), the switchgear S1 is switched to the closed state, and then the switches 23, 26,
29 is turned off and the inverter 1 is started. Therefore,
The inverter 1 is started based on the voltage soft start control, the frequency soft start control, and the current soft start control.

When the switchgear S3 is switched to the open state during the interconnection operation in which the switchgear S1 and the switchgear S3 are closed, or when the power failure detector 4 detects a power failure, the switchgear S1 is temporarily turned on. After switching to the open state and confirming that the switchgear S3 is in the open state, the switches 23, 26 and 29 are turned on to stop the inverter 1 (that is, the output voltage V and the output frequency of the inverter 1). (After lowering F to their respective set minimum values), the switchgear S1 is switched to the closed state, and then the switches 23 and 2
6 and 29 are turned off and the inverter 1 is started. Therefore, the inverter 1 is started based on the voltage soft start control, the frequency soft start control, and the current soft start control.

Therefore, based on the output command, the inverter 1 is controlled so as to decrease the output voltage V of the inverter 1 to the set minimum value, and then the switchgear S1 is switched to the closed state.
Next, the control means 100 that controls the inverter 1 so as to gradually increase the output voltage V is configured using the control device C. Further, in the process of gradually increasing the output voltage V by the control means 100, the allowable current value setting means 101 for setting the allowable current value Is to be gradually increased from the set minimum value, the operation control section 22, the switch 29 and the second reference voltage. It is configured using the generation circuit 30. Further, the control means 100 controls the inverter 1 based on the output command so that the output frequency F of the inverter 1 also decreases to the set minimum value, and in the process of gradually increasing the output voltage V, the output frequency F also gradually increases. The output current I of the inverter 1 is detected in the process of gradually controlling the output voltage V while controlling the inverter 1 to
When the output current I becomes larger than the allowable current value Is set to be gradually increased, the inverter 1 is adjusted so that both the output voltage V and the output frequency F are adjusted so that the output current I becomes equal to or less than the allowable current value Is. It is configured to control.

The switchgear S3 and the power failure detection device 4 are in a power supply state in which electric power is being supplied from the commercial power source 6 to the external load device 6 and a cutoff state in which the supply of electric power from the commercial power source 6 to the external load device 6 is cut off. It functions as a detection means for detecting the state.

[Other Embodiment] Another embodiment will be described below. In the above embodiment, the control means 100 is configured so that the inverter 1 is controlled so that both the output voltage V and the output frequency F of the inverter 1 are gradually increased from their respective set minimum values based on the output command. However, instead of this, the inverter 1 may be controlled so that only the output voltage V is gradually increased from the set minimum value while the output frequency F is kept constant at the rated frequency. Good. In this case, in the control device C, the third reference voltage generating circuit 27 is configured to always generate a constant reference voltage.

In the above embodiment, in the control means 100, the output current I of the inverter 1 is detected in the process of gradually increasing the output voltage V, and when the output current I becomes larger than the allowable current value Is, Output current I is allowable current value I
The case where the inverter 1 is configured to be controlled so as to adjust both the output voltage V and the output frequency F so as to be s or less has been illustrated. Instead of this, the output voltage V
In the process of gradually increasing, the output current I of the inverter 1 is detected, and when the output current I becomes larger than the allowable current value Is, the output current I becomes equal to or less than the allowable current value Is,
The inverter 1 may be controlled so as to adjust the output voltage V. In this case, the second correction circuit 33 may be omitted in the control device C. In the process of gradually increasing the output voltage V, the output current I of the inverter 1
Is detected and the output current I becomes larger than the allowable current value Is, the inverter 1 is controlled so as to adjust the output frequency F so that the output current I becomes equal to or less than the allowable current value Is. May be. In this case, the first correction circuit 32 may be omitted in the control device C.

A set minimum value when gradually increasing the output voltage V in the voltage soft start control, a set minimum value when gradually increasing the output frequency F in the frequency soft start control, and an allowable current value Is gradually increased in the current soft start control The minimum setting value at the time of setting can be appropriately changed. For example, in the above embodiment, the minimum setting value in the voltage soft start control is set to 0V, but it may be set to a value other than 0V. In the above embodiment, the minimum setting value in the current soft start control is set to 0A.
It may be set to other than.

Gradual increase rate of the output voltage V in the voltage soft start control (corresponding to a predetermined time in the voltage soft start period), gradually increasing rate of the output frequency F in the frequency soft start control (corresponding to a predetermined time in the frequency soft start period) , And the gradual increase rate of the permissible current value Is in the current soft start control (corresponding to a predetermined time in the current soft start period) are appropriately set according to the specifications of the inverter 1, the capacity of the external load device 5, the type, etc. can do.

In addition to the configuration shown in the above embodiment, the control means 100 allows the output current I when the output current I of the inverter 1 becomes smaller than the allowable current value Is in the process of gradually increasing the output voltage V. A function of increasing the output voltage V, the output frequency F, or both the output voltage V and the output frequency F may be added so as to approach the current value Is.

The type of the fuel cell 17 is not limited to the phosphoric acid electrolyte type illustrated in the above embodiment, and various types such as a solid electrolyte type can be used.

It should be noted that reference numerals are given in the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a block diagram of a power supply device using a fuel cell according to an embodiment of the present invention.

FIG. 2 is a block diagram of a control device in a power supply device using a fuel cell.

FIG. 3 is a block diagram of a fuel cell power generation unit in a power supply device using a fuel cell.

FIG. 4 is a diagram showing a state in which the reference voltage gradually changes in each of voltage soft start control, current soft start control, and frequency soft start control.

FIG. 5 is a diagram showing a relationship between an output current and an output voltage when the output voltage is lowered.

FIG. 6 is a diagram showing a gradual increase change in output voltage in voltage soft start control, a gradual increase change in allowable current value in current soft start control, and a gradual increase change in output frequency in frequency soft start control.

[Explanation of symbols]

 1 orthogonal transformation means 4, S3 detection means 5 external load device 6 commercial power supply 17 fuel cell 100 control means 101 allowable current value setting means S1 opening / closing means

Claims (4)

[Claims] 1. An external load device (5) is connected to an orthogonal conversion means (1) for converting output DC power of a fuel cell (17) into AC power, the orthogonal conversion means (1) and the external load device (1). 5) is provided with an opening / closing means (S1) for opening / closing the connection with the orthogonal transformation means (S1) based on an output command for outputting the AC power output from the orthogonal transformation means (1) to the external load device (5). After controlling the orthogonal transformation means (1) so as to reduce the output voltage of 1) to the set minimum value, the opening / closing means (S1) is switched to the closed state, and then the output voltage is gradually increased. A power supply device using a fuel cell, which is provided with a control means (100) for controlling the orthogonal transformation means (1), wherein an allowable current value is set to a minimum in a process in which the control means (100) gradually increases the output voltage. Set to gradually increase from the value The allowable current value setting means (101) is provided, and the control means (100) detects the output current of the orthogonal transformation means (1) in the process of gradually increasing the output voltage, and the output current is the allowable current value. When it becomes larger than the current value,
The quadrature conversion is performed so that the output voltage, the output frequency of the quadrature conversion means (1), or both the output voltage and the output frequency are adjusted so that the output current becomes equal to or less than the allowable current value. A fuel cell based power supply configured to control the means (1). 2. The control means (100) controls the orthogonal transformation means (1) so as to reduce the output frequency of the orthogonal transformation means (1) to a set minimum value based on the output command, 2. The power supply device using a fuel cell according to claim 1, wherein in the process of gradually increasing the output voltage, the orthogonal transforming means (1) is controlled so as to gradually increase the output frequency. 3. The control means (100) controls the output current to approach the allowable current value when the output current becomes smaller than the allowable current value in the process of gradually increasing the output voltage. The fuel cell according to claim 1 or 2, which is configured to control the orthogonal transformation means (1) so as to adjust an output voltage, the output frequency, or both the output voltage and the output frequency. Use power supply. 4. A power supply state in which the external load device (5) is connected to a commercial power supply (6), and electric power is supplied from the commercial power supply (6) to the external load device (5), Detection means (S3) for detecting an interruption state in which the supply of electric power from the commercial power source (6) to the external load device (5) is interrupted,
(4) is provided, and the control means (100) includes the detection means (S3),
Based on the detection information of (4), the detection means (S3),
(4) is configured to execute the control based on the output command after opening the opening / closing means (S1) when the disconnection state is detected during the interconnection operation for detecting the power supply state. A power supply device using a fuel cell according to claim 1, 2, or 3.