JP6568441B2 - FUEL CELL DEVICE AND CONTROL METHOD FOR FUEL CELL DEVICE - Google Patents

Description

  The present invention relates to a fuel cell device and a control method for the fuel cell device.

  Conventionally, when a fuel cell device is installed in a customer facility, a main CT (also referred to as a current transformer or a current sensor) attached to the main is a single type corresponding to the fuel cell device. However, in recent years, with the diversification of the capacity of fuel cell devices, it is desired to use not only the standard CT but also a CT having a rated current different from the standard. For this reason, there has been an increasing demand for replacing a plurality of types of CTs so that they can be attached. Although a configuration that meets such a demand is not known, there is an example of a configuration in which a plurality of CTs each having different measurable current sizes are used simultaneously (for example, see Patent Document 1).

JP 2013-50385 A

  However, in the configuration in which different types of CT are used at the same time, it is necessary to install a plurality of CTs, which increases the installation cost. Therefore, it is still desirable to replace it with the required type of CT.

  When replacing CT here, it is necessary to set correctly the current conversion coefficient according to CT in the apparatus or software which converts the output from CT into a current measurement value. However, when there are a plurality of types of current conversion coefficients for CT attached to the main trunk, it is possible that the current conversion coefficient for the attached CT and the current conversion coefficient set in the apparatus or software may be different. In that case, it will be converted into an incorrect current measurement value.

  Accordingly, the present invention has been made in view of the above points, and provides a primary current fuel cell device and a control method for the fuel cell device that can be converted into a correct current measurement value from a secondary current of an attached current sensor. With the goal.

In order to solve the above problems, a fuel cell device according to an embodiment of the present invention includes:
A secondary battery is connected to the grid and is provided between the fuel cell, the power conversion device that controls the fuel cell, the power conversion device and the grid, and obtains a secondary current corresponding to the primary current flowing through the main trunk of the grid. A fuel cell device comprising a current sensor and an internal load,
Obtaining a first measurement value corresponding to the secondary current when the internal load is in a stopped state;
Obtaining a second measurement value corresponding to the secondary current when the internal load is in operation;
Calculating a difference between the first measurement value and the second measurement value as a third measurement value;
A control unit that converts the secondary current into the primary current based on the third measurement value and a current flowing through the internal load when the internal load is in an operating state ;
The current flowing through the internal load when the internal load is in an operating state is known .

In order to solve the above problems, a control method of a fuel cell device according to an embodiment of the present invention includes:
A secondary battery is connected to the grid and is provided between the fuel cell, the power conversion device that controls the fuel cell, the power conversion device and the grid, and obtains a secondary current corresponding to the primary current flowing through the main trunk of the grid. A control method of a fuel cell device comprising a current sensor that performs an internal load,
Obtaining a first measurement value corresponding to the secondary current when the internal load is in a stopped state;
Obtaining a second measurement value corresponding to the secondary current when the internal load is in operation;
Calculating a difference between the first measurement value and the second measurement value as a third measurement value;
Wherein the third measurement value, the internal load is based on the current flowing through the internal load when the operating condition, viewed including the steps of converting the secondary current in the primary current,
The current flowing through the internal load when the internal load is in an operating state is known .

  According to the fuel cell device and the control method of the fuel cell device of the present invention, the current conversion coefficient of the attached current sensor can be set correctly.

1 is a schematic diagram of a power supply system according to an embodiment. It is a block diagram which shows an example of the circuit which converts the secondary current of a current sensor, and acquires the electric current which flows into a power line. It is a graph which shows the relationship between the primary current of a current sensor, and the voltage value of a current sensor. (A) Current sensor with CT ratio N (b) Current sensor with CT ratio 2N It is a flowchart which shows the method of determining the current conversion coefficient of a current sensor. Based on the graph of FIG. 3, the voltage value of the current sensor when the auxiliary machine is in an operating state or a stopped state is shown. It is a flowchart of the determination process based on a 3rd measured value. 10 is a flowchart of a determination process based on a third measurement value according to Modification Example 1. It is the flowchart which added the confirmation input step to the flowchart of FIG. It is a flowchart which shows the method of determining a current conversion coefficient using the average value of a measured value.

(Embodiment)
Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings.

[System configuration]
FIG. 1 is a schematic diagram of a power supply system 1 according to an embodiment. The power supply system 1 includes a main distribution board 3 (also simply referred to as a main trunk) that receives power from the grid 8 and outputs single-phase three-wire U-phase and W-phase power, and U-phase and W-phase currents. Current sensor U41 and current sensor W42 (hereinafter collectively referred to as current sensor 4), load U51 and load W52 (hereinafter collectively referred to as load 5) connected to main distribution board 3, and dispersion The mold power supply device 2 is provided. The main distribution board 3 is connected to single-phase three-wire U-phase, O-phase, and W-phase power lines. The O-phase power line is grounded, and the U-phase and W-phase power lines are connected to the distributed power supply device 2. A load U51 is connected between the U phase and the O phase, and a load W52 is connected between the W phase and the O phase. The distributed power supply device 2 can supply power to the load U51 and the load W52 through the U-phase and W-phase power lines.

  The distributed power supply device 2 according to an embodiment is a fuel cell device 2. The distributed power supply device 2 is not limited to this, and may be a storage battery, or a power supply device having another power generation method such as solar power generation or wind power generation. The fuel cell device 2 according to the present embodiment includes a control unit 21, a cell stack (fuel cell) 22, an auxiliary machine 23 (auxiliary machine U231, auxiliary machine W232, and auxiliary machine X233), an inverter 24, and an interconnection. A switch 25 and an auxiliary machine switch 26 are provided.

  The control unit 21 of the fuel cell device 2 is indicated by broken lines in the cell stack 22, the auxiliary machine X233, the inverter (power conversion device) 24, the interconnection switch 25, the auxiliary machine switch 26, and the current sensor 4. Connected via a communication line. The communication line may be wired or wireless. The control unit 21 can transition the states of the auxiliary machine U231 and the auxiliary machine W232 to the operating state or the stopped state by the auxiliary machine switch 26. In addition, the control unit 21 can control the auxiliary machine X233 to generate power in the cell stack 22. Further, the control unit 21 can convert the power generated by the cell stack 22 by the inverter 24 and supply it to the load 5 by controlling the interconnection switch 25 to be turned on. The control unit 21 can acquire U-phase and W-phase currents measured by the current sensor 4.

  The cell stack 22 receives fuel, air, and water supplied from the auxiliary machine 23 to generate power, and outputs DC power to the inverter 24. The inverter 24 converts the DC power generated by the cell stack 22 into AC power and outputs the AC power to the U-phase and W-phase power lines connected to the main distribution board 3 via the interconnection switch 25.

  The auxiliary machine X233 is a peripheral device necessary for the cell stack 22 to generate power, and includes, for example, a fuel supply system, an air supply system, a water treatment system, or a cooling system. In the present embodiment, the auxiliary machine U231 and the auxiliary machine W232 are heaters and are also referred to as internal loads of the fuel cell device 2. These heaters are, for example, anti-freezing heaters, ignition heaters, or combustion catalyst heaters provided for operating the fuel cell, but are not limited thereto.

  The current sensor 4 is a current transformer (CT), and outputs a secondary current having a ratio (current transformation ratio or CT ratio) according to the number of turns on the primary side and the secondary side with respect to the input primary current. The CT ratio is expressed as, for example, 100 A / 1 A. In this case, when a current of 100 A is input as a primary current, a current of 1 A is output as a secondary current. The current sensor U41 and the current sensor W42 are provided in each of the U-phase and W-phase power lines connected to the main distribution board 3, and a current flowing through each power line is input as a primary current.

  The load U51 and the load W52 are connected to single-phase U-phase and W-phase power lines, respectively, and are supplied with power from the grid 8 via the main distribution board 3 or supplied with power from the fuel cell device 2. The

[Current sensor]
In the present embodiment, the control unit 21 of the fuel cell device 2 converts the secondary current of the current sensor 4 and acquires currents flowing through the U-phase and W-phase power lines. FIG. 2 is a block diagram showing an example of a circuit that converts the secondary current of the current sensor 4 and acquires currents flowing through the U-phase and W-phase power lines. The secondary current output from the current sensor 4 flows through the resistor 43, whereby a voltage is output across the resistor 43. Here, when the secondary current, the resistance value of the resistor 43, and the voltages output to both ends of the resistor 43 are i, R, and v, respectively, the relationship of v = Ri is established.

  The voltage output across the resistor 43 is input to the amplifier circuit (full range) 44 or the amplifier circuit (enlarged) 45. The amplifier circuit (full range) 44 or the amplifier circuit (enlargement) 45 amplifies the input voltage and outputs it to the A / D converter 46. Here, the amplifier circuit (full range) 44 and the amplifier circuit (enlarged) 45 are selectively used in accordance with the situation, and will be described later.

  The A / D converter 46 acquires a voltage value corresponding to the secondary current of the current sensor 4 from the amplifier circuit (full range) 44 or the amplifier circuit (enlargement) 45. The A / D converter 46 converts the acquired analog voltage value into a digital value and outputs the digital value to the processor 47.

  The processor 47 calculates the average value or effective value of the voltage from the digital voltage waveform acquired from the A / D converter 46. Further, the processor 47 converts the average value or effective value of the voltage into the average value or effective value of the primary current input to the current sensor 4 based on the current conversion coefficient of the current sensor 4.

  The resistor 43, the amplifier circuit (full range) 44, the amplifier circuit (enlargement) 45, the A / D converter 46, or the processor 47 included in FIG. 2 may all be included in the control unit 21 of the fuel cell device 2. Alternatively, a part may be included in the control unit 21. Hereinafter, the processor 47 will be described as being included in the control unit 21.

  As described above, the control unit 21 amplifies the secondary current output from the current sensor 4 and obtains a voltage value obtained by converting it into a digital value, and an average value or an effective value (hereinafter referred to as “the obtained voltage value”). , Which is also referred to as a voltage value of the current sensor 4). Further, the control unit 21 converts the voltage value of the current sensor 4 based on the current conversion coefficient of the current sensor 4, and averages or the effective value (hereinafter also referred to as the primary current value) of the primary current input to the current sensor. To get. The current conversion coefficient will be described later.

  Here, the proper use of the amplification circuit (full range) 44 and the amplification circuit (enlargement) 45 will be described.

  The amplifier circuit (full range) 44 receives a voltage input in a range (full range) corresponding to the rated secondary current of the current sensor 4 and amplifies the input voltage value according to the rated input of the A / D converter 46. To do. The amplifier circuit (full range) 44 has an advantage that it can cope with the range of the rated secondary current of the current sensor 4. On the other hand, in the amplification circuit (full range) 44, when the secondary current is very small, the output voltage value to the A / D converter 46 decreases, and the error in the A / D converter 46 may increase. Has disadvantages.

  The amplification circuit (enlargement) 45 amplifies the voltage corresponding to the minute secondary current in accordance with the rated input of the A / D converter 46 when the secondary current of the current sensor 4 is minute. The amplifier circuit (enlarged) 45 can output a voltage in accordance with the rated input of the A / D converter 46 even when the secondary current is very small, so that an error in the A / D converter 46 can be prevented from increasing. Has merit. On the other hand, the amplifier circuit (enlarged) 45 has a demerit that the voltage output when the secondary current is large exceeds the rated input of the A / D converter 46.

  As described above, the amplification circuit (full range) 44 and the amplification circuit (enlargement) 45 have advantages and disadvantages, respectively. As an example of proper use, the amplifier circuit (enlarged) 45 may be used if the secondary current is within 5% of the rated secondary current, and the amplifier circuit (full range) 44 may be used otherwise. It is not limited to this example.

[Current conversion coefficient]
FIG. 3 is a graph showing the relationship between the input primary current to the current sensor 4 and the voltage value of the current sensor 4. In the graph of FIG. 3, the horizontal axis indicates the primary current input to the current sensor 4, and the vertical axis indicates the voltage value of the current sensor 4. 3A shows a case where the rated input current of the current sensor 4 is I _in (A), and FIG. 3B shows a case where the rated input current of the current sensor 4 is 2I _in (A). That is, the rated input current of the current sensor 4 in FIG. 3B is twice that in FIG.

In FIG. 3A, the primary current is I _in (A), whereas the voltage value is V _out (V). In this case, the current conversion coefficient of the current sensor 4 is represented by K1 (A / V ), K1 = _Iin / _Vout . In FIG. 3B, the primary current is 2I _in (A), whereas the voltage value is V _out (V). In this case, the current conversion coefficient of the current sensor 4 is represented by K2 (A / V), K2 = 2I _in / V _out is calculated. That is, in FIGS. 3A and 3B, the slope of the graph corresponds to the current conversion coefficient.

  Further, the CT ratios of the current sensor 4 in FIGS. 3A and 3B are N and 2N, respectively. Further, the current conversion coefficient of the current sensor 4 in FIG. 3B is twice that in FIG. Hereinafter, the current sensor 4 in FIG. 3A is also referred to as a current sensor 4 having a CT ratio N, and the current sensor 4 in FIG. 3B is also referred to as a current sensor 4 having a CT ratio 2N. The fuel cell device 2 according to the present embodiment can be connected to a current sensor 4 having a CT ratio N and a current sensor 4 having a CT ratio 2N, but is not limited thereto, and can be connected to a current sensor 4 having another CT ratio. You may do it.

  The current conversion coefficient is different between the case where the voltage value of the current sensor 4 is calculated using the amplifier circuit (full range) 44 and the case where the voltage value is calculated using the amplifier circuit (enlargement) 45. The current conversion coefficients in each case can be converted into each other based on the ratio between the amplification factor of the amplification circuit (full range) 44 and the amplification factor of the amplification circuit (enlargement) 45.

[Determination of current conversion coefficient]
As described above, the control unit 21 including the processor 47 can obtain the primary current value by converting the voltage value of the current sensor 4 based on the current conversion coefficient of the current sensor 4. Here, when the current conversion coefficient of the current sensor 4 actually attached to the power line does not match the current conversion coefficient set in the control unit 21, the primary current value acquired by the control unit 21 is the actual primary value. It will be different from the current value. Here, the control unit 21 of the fuel cell device 2 according to the present embodiment can determine the current conversion coefficient of the current sensor 4 based on the secondary current of the current sensor 4 that is actually attached. By doing in this way, it can prevent that the primary current value which the control part 21 acquires differs from an actual primary current value. Hereinafter, the specific content of the control method of the fuel cell device 2 according to the embodiment including the method for determining the current conversion coefficient will be described.

  FIG. 4 is a flowchart showing how the control unit 21 determines the current conversion coefficient of the current sensor 4. Hereinafter, although it demonstrates along the flowchart of FIG. 4, the method to determine the current conversion coefficient of the current sensor U41 attached to the U-phase power line is demonstrated here. The same applies to the method of determining the current conversion coefficient of the current sensor W42 attached to the W-phase power line. In the present embodiment, it is assumed that the current flowing through the load 5 is always constant. It is assumed that the current that flows when the auxiliary machine 23 is in an operating state is known.

  First, the control unit 21 turns off the auxiliary machine switch 26 and causes the auxiliary machine U231 to transition to a stopped state (step S102).

  Next, the control unit 21 acquires the voltage value of the current sensor U41 when the auxiliary machine U231 is in the stopped state as the first measurement value (step S103). At this time, the primary current (current flowing through the U-phase power line) input to the current sensor U41 is only the current flowing through the load U51.

  Here, FIG. 5 shows the voltage value of the current sensor 4 when the auxiliary machine 23 is in the operating state or the stopped state, based on the graph of FIG. In the graph of FIG. 5, the horizontal axis and the vertical axis are the same as those in FIG. The point indicated as Off on the horizontal axis in FIG. 5 indicates the input primary current to the current sensor 4 when the auxiliary machine 23 is in a stopped state. The point indicated by res1 on the vertical axis in FIG. 5 indicates the voltage value of the current sensor 4 when the auxiliary machine 23 is in a stopped state, that is, the first measured value. 5A shows a case where the current conversion coefficient of the current sensor 4 is K1, and FIG. 5B shows a case where the current conversion coefficient of the current sensor 4 is K2.

  Next, the control unit 21 turns on the auxiliary machine switch 26 to shift the auxiliary machine U231 to the operating state (step S104).

  Next, the control unit 21 acquires the voltage value of the current sensor U41 when the auxiliary machine U231 is in an operating state as the second measurement value (step S105). At this time, the primary current (current flowing through the U-phase power line) input to the current sensor U41 is the sum of the current flowing through the load U51 and the current flowing through the auxiliary device U231.

  Here, the point indicated as On on the horizontal axis in FIG. 5 indicates the primary current input to the current sensor 4 when the auxiliary machine 23 is in an operating state. Further, the point indicated by res2 on the vertical axis in FIG. 5 indicates the voltage value of the current sensor 4 when the auxiliary machine 23 is in operation, that is, the second measured value.

Next, the control unit 21 calculates a difference between the first measurement value and the second measurement value to calculate a third measurement value (step S106). As described above, the first and second measurement values are res1 and res2, respectively. If the third measurement value is res3, the third measurement value is calculated by the following equation (1).
res3 = res2-res1 (1)

  Here, when res2-res1 in FIG. 5A is compared with res2-res1 in FIG. 5B, the magnitude of the third measured value to be calculated according to the difference in the current conversion coefficient of the current sensor 4 is large. It can be understood that they are different.

  Here, as described above, in the present embodiment, since the current flowing through the load U51 is always constant, the third measured value is a voltage value corresponding to the current flowing through the auxiliary device U231. That is, the voltage value corresponding to the current flowing through the auxiliary machine U231 is the voltage value of the current sensor U41 when the current flowing through the auxiliary machine U231 is the primary current of the current sensor U41.

  Next, the control unit 21 performs determination based on the third measurement value in order to determine the current conversion coefficient of the current sensor U41 (S107). FIG. 6 is a flowchart of the determination process based on the third measurement value. Hereinafter, the determination process based on the third measurement value will be described with reference to the flowchart of FIG.

  First, the control unit 21 determines whether or not the third measurement value is within the first determination range including the first determination value (step S201). Here, the first determination value is a voltage value corresponding to the current flowing through the auxiliary device U231 when the current conversion coefficient of the current sensor U41 is K1. In this case, since the current flowing through the load U51 is always constant in the present embodiment as described above, the first determination value is equal to the third measurement value when the current conversion coefficient of the current sensor U41 is K1. It can also be said that the first determination value is based on the current flowing through the auxiliary device U231 when the auxiliary device U231 is in an operating state.

  The first determination range is a range including the first determination value, and A1 ± c (A1: first determination value, c: predetermined value) can be set as the upper and lower limits, but is not limited thereto. It is good also as c1 or more and A1 + c2 or less (c1 and c2 are respectively predetermined values).

  When the third measurement value is within the first determination range (step S201: YES), the control unit 21 determines that the current conversion coefficient of the current sensor U41 attached to the U phase is K1 (step S202). . Thereafter, the control unit 21 ends the flowchart process of FIG. 6, returns to the flowchart of FIG. 4, and ends the process. When the third measurement value is not within the first determination range (step S201: NO), the control unit 21 proceeds to step S203.

  Subsequently, the control unit 21 determines whether or not the third measurement value is within the second determination range including the second determination value (step S203). Here, the second determination value is a voltage value corresponding to the current flowing through the auxiliary device U231 when the current conversion coefficient of the current sensor U41 is K2. In this case, since the current flowing through the load U51 is always constant in the present embodiment as described above, the second determination value is equal to the third measurement value when the current conversion coefficient of the current sensor U41 is K2. It can also be said that the second determination value is based on the current flowing through the auxiliary device U231 when the auxiliary device U231 is in an operating state.

  Further, the second determination range is a range including the second determination value, and similarly to the first determination value, A2 ± c (A2: second determination value, c: predetermined value) can be set as the upper and lower limits. It is not limited to.

  When the third measurement value is within the second determination range (step S203: YES), the control unit 21 determines that the current conversion coefficient of the current sensor U41 attached to the U phase is K2 (step S204). . Thereafter, the control unit 21 ends the flowchart process of FIG. 6, returns to the flowchart of FIG. 4, and ends the process. When the third measurement value is not within the second determination range (step S203: NO), the control unit 21 proceeds to step S205.

  Subsequently, since the third measurement value is not within the first and second determination ranges, the control unit 21 cannot determine the current conversion coefficient of the current sensor U41 attached to the U phase. Error information indicating that the coefficient cannot be determined is displayed (step S205). Thereafter, the control unit 21 ends the flowchart process of FIG. 6, returns to the flowchart of FIG. 4, and ends the process.

  The control method of the fuel cell device 2 according to the present embodiment has been described above with reference to FIGS. As described above, the control unit 21 of the fuel cell device 2 acquires the voltage value of the current sensor 4 while controlling the state of the auxiliary machine 23 that is an internal load, whereby the current sensor 4 attached to the power line. Current conversion factor can be determined. As a result, even when the current conversion coefficient of the current sensor 4 attached to the power line is different from that assumed, the situation where the primary current value acquired by the control unit 21 is different from the actual primary current value is prevented. be able to. That is, the control unit 21 can obtain a correct current measurement value based on the determined current conversion coefficient of the current sensor 4. By doing in this way, the trouble in installation and setting of the current sensor can be avoided, and the fuel cell can be smoothly generated. In addition, the reliability of fail safe is improved. That is, it is possible to determine a current conversion coefficient that correctly corresponds to the current sensor 4 attached to the power line, or to display error information indicating that the current conversion coefficient cannot be determined. In addition, since an internal load can be used to determine the current conversion coefficient, a new load for determining the current conversion coefficient is not necessary.

(Modification 1)
In the present embodiment, voltage values are acquired as the first and second measurement values, and ranges indicated by voltage values are used as the first and second determination ranges. In the first modification, a case where current values are acquired as the first and second measurement values will be described.

  A control method of the fuel cell device 2 according to Modification 1 will be described with reference to the flowcharts of FIGS. 4 and 7. In the flowchart of FIG. 4, description of common parts with the control method of the fuel cell device 2 according to the present embodiment is omitted.

  In step S103 of FIG. 4, the control unit 21 of the fuel cell device 2 acquires the voltage value of the current sensor 4, and calculates the first temporary current value using the temporary current conversion coefficient set automatically or manually. . The control unit 21 sets the first temporary current value as the first measured value. Similarly, in step S105 in FIG. 4, the control unit 21 acquires the voltage value of the current sensor 4, calculates the second temporary current value using the temporary current conversion coefficient, and sets the second temporary current value to the second value. Measured value.

  Here, the temporary current conversion coefficient is temporarily set and is selected from the current conversion coefficients of a plurality of types of current sensors 4 that can be connected to the fuel cell device 2. In the first modification, since the current sensor 4 with CT ratio N and the current sensor 4 with CT ratio 2N can be connected to the fuel cell device 2, the temporary current conversion coefficient is K1 or K2. Here, it is assumed that the provisional current conversion coefficient is K1.

  In step S106 of FIG. 4, the control unit 21 calculates a third measurement value. The third measured value calculated here is a third temporary current value converted from the voltage value corresponding to the current flowing through the auxiliary machine U231 using the temporary current conversion coefficient.

  In step S107 of FIG. 4, the control unit 21 performs determination based on the third measurement value in order to determine the current conversion coefficient of the current sensor U41. FIG. 7 is a flowchart of the determination process based on the third measurement value according to the first modification. Hereinafter, a method of performing determination based on the third measurement value will be described with reference to the flowchart of FIG.

  The control unit 21 determines whether or not the third measurement value is within a determination range including the determination value (step S301). Here, the determination value is a current value flowing through the auxiliary machine U231. The determination range is a range including a determination value, and A ± c (A: determination value, c: predetermined value) can be set as the upper and lower limits, but is not limited thereto, and is not less than A−c1 and A + c2. The following (c1 and c2 may be predetermined values) may be used.

  When the third measurement value is within the determination range (step S301: YES), the control unit 21 determines the temporary current conversion coefficient as the current conversion coefficient (step S302).

  When the third measurement value is not within the determination range (step S301: NO), the control unit 21 stores information indicating that the third measurement value related to the current temporary current conversion coefficient is out of the determination range, It is determined whether there is a next candidate for the current conversion coefficient (step S303).

  When there is a next candidate for the temporary current conversion coefficient (step S303: YES), the control unit 21 changes the temporary current conversion coefficient to a new value (step S304). In the first modification, the current provisional current conversion coefficient is K1, and the remaining candidate is K2, so the provisional current conversion coefficient is set to K2. Then, the control part 21 complete | finishes the process of the flowchart of FIG. If there is no next candidate for the temporary current conversion coefficient (step S303: NO), the control unit 21 displays error information indicating that the current conversion coefficient cannot be determined (step S305), and ends the process of the flowchart of FIG.

  When the temporary current conversion coefficient is changed, the control unit 21 executes the process of the flowchart of FIG. 4 from the beginning, acquires the third measurement value related to the new temporary current conversion coefficient, and performs the determination.

  The control method of the fuel cell device 2 according to Modification 1 has been described above. By doing in this way, a current conversion factor can be determined using the average value or effective value of the primary current input to the current sensor 4 that is normally output by the control unit 21, and a correct current measurement value can be obtained. . That is, it is not necessary to use the voltage value of the current sensor 4 that is an intermediate value of the arithmetic processing of the control unit 21 and is not normally output.

(Modification 2)
In the present embodiment, when the current conversion coefficient of the current sensor 4 is determined, it is not determined whether or not the current conversion coefficient is as expected. In the second modification, a description will be given of a configuration for obtaining confirmation from the outside regarding the determined current conversion coefficient.

  FIG. 8 is a flowchart in which a confirmation input step is added to the flowchart of FIG. The description of steps S201 to S205 is the same as in FIG.

  The control unit 21 of the fuel cell apparatus 2 determines whether the determined current conversion coefficient is intended or not after the current conversion coefficient is determined in step S202 or step S204. A conversion factor is displayed and a confirmation input is acquired (step S206). The confirmation input may be performed by an operator who has attached the current sensor 4 or may be performed by another person. Moreover, the control part 21 may transmit the determined current conversion coefficient to a server via a network, and may acquire confirmation input from a server.

  Subsequently, the control unit 21 determines whether or not the determined current conversion coefficient is confirmed to be correct (step S207). If it is confirmed that it is correct (step S207: YES), the processing of the flowchart of FIG. 6 is terminated. If it is not confirmed to be correct (step S207: NO), the control unit 21 displays error information indicating that the current conversion coefficient is not assumed (step S208), and ends the processing of the flowchart of FIG.

  The control method for the fuel cell device 2 according to Modification 2 has been described above. By doing so, the possibility of erroneous setting of the current conversion coefficient is further reduced. Further, even when an unintended type of current sensor 4 is mistakenly installed, an error can be detected.

(Modification 3)
In the present embodiment, the current flowing through the load 5 is always constant. In Modification 3, a case where the current flowing through the load 5 varies will be described.

  When the current flowing through the load 5 varies, the current flowing through the load 5 at the time of step S103 may be different from the current flowing through the load 5 at the time of step S105 in the flowchart of FIG. In this case, the third measurement value is not necessarily equal to the voltage value corresponding to the current flowing through the auxiliary machine U231. In the control method of the fuel cell device 2 according to the present embodiment, the first and second determination ranges having the determination margin with respect to the first and second determination values are used.

  Here, when there is a sudden large fluctuation in the current flowing through the load 5, there is a possibility that the first and second determination ranges cannot cope. However, even in such a case, it is possible to cope with the first and second determination ranges by acquiring a plurality of measurement values over a predetermined time and reducing the fluctuation range by taking an average of these.

  FIG. 9 is a flowchart showing a method for determining a current conversion coefficient using an average value of measured values. Here, a method for determining the current conversion coefficient of the current sensor U41 attached to the U-phase power line will be described, but the same applies to the W-phase power line. First, the control unit 21 of the fuel cell device 2 prepares to obtain the average value of the measurement values, and measures the average of the first measurement value integrated value (int1) and the second measurement value integrated value (int2). The number of times (J) is initialized to 0 (step S401).

  Subsequently, the control unit 21 determines whether or not the number of measurements is a predetermined number or more (step S402). When the number of measurements is equal to or greater than the predetermined number (step S402: YES), the control unit 21 proceeds to step S408. When the number of measurements is not equal to or greater than the predetermined number (less than the number of measurements) (step S402: NO), the control unit 21 Advances to step S403.

  Subsequently, the control unit 21 turns off the auxiliary machine switch 26 and causes the auxiliary machine U231 to transition to a stopped state (step S403).

  Subsequently, the control unit 21 acquires the voltage value of the current sensor U41 when the auxiliary machine U231 is in a stopped state as a first measurement value, and adds it to the first measurement value integrated value (step S404).

  Subsequently, the control unit 21 turns on the auxiliary machine switch 26 to shift the auxiliary machine U231 to the operating state (step S405).

  Subsequently, the control unit 21 acquires the voltage value of the current sensor U41 when the auxiliary machine U231 is in the operating state as the second measurement value, and adds it to the second measurement value integrated value (step S406).

  Subsequently, the control unit 21 adds 1 to the number of measurements (step S407). Subsequently, the control unit 21 returns to step S402 and again determines the number of measurements.

  When the number of measurements is equal to or greater than the predetermined number, the control unit 21 determines the average value of the first measurement values (hereinafter, the first measurement value) based on the first measurement value integrated value, the second measurement value integrated value, and the measurement count. Similar to the value, it is also expressed as res1) and an average value of the second measurement values (hereinafter, also expressed as res2 as in the case of the second measurement value) (step S408). Here, the average values of the first and second measurement values are calculated by the equation res1 = int1 / J and the equation res2 = int2 / J, respectively.

  Subsequently, the control unit 21 calculates the difference between the average value of the first measurement values and the average value of the second measurement values using the equation (1) shown in the description related to step S106 in FIG. A third measurement value (res3) is calculated (step S409).

  Subsequently, the control unit 21 performs determination based on the third measurement value in order to determine the current conversion coefficient of the current sensor U41 (S410). The determination based on the third measurement value is performed along the flowchart of FIG. After the determination based on the third measurement value ends, the control unit 21 ends the process of the flowchart of FIG.

  The control method for the fuel cell device 2 according to Modification 3 has been described above. The number of measurements is preferably at least twice, and the average value of the first and second measurement values is preferably calculated from at least two measurement values. By doing in this way, even when there is a fluctuation in the current flowing through the load 5, or even when this fluctuation is sudden and large, it can be dealt with. That is, the current sensor 4 can be installed and set even when the load 5 is in operation.

  Although the present invention has been described based on the drawings and examples, it should be noted that those skilled in the art can easily make various modifications and corrections based on the present disclosure. Therefore, it should be noted that these variations and modifications are included in the scope of the present invention. For example, the functions included in each component, each step, etc. can be rearranged so that there is no logical contradiction, and multiple components, steps, etc. can be combined or divided into one It is. Further, although the present invention has been described centering on an apparatus, the present invention can also be realized as a method including steps executed by each component of the apparatus. Further, although the present invention has been described mainly with respect to the apparatus, the present invention can also be realized as a method, a program executed by a processor included in the apparatus, or a storage medium storing the program, and is within the scope of the present invention. It should be understood that these are also included.

1 Power supply system 2 Distributed power supply device (fuel cell device)
21 Control unit 22 Cell stack (fuel cell)
23 Auxiliary machine 24 Inverter (power conversion equipment)
25 Link Switch 26 Auxiliary Switch 3 Main Power Distribution Board 41 Current Sensor U
42 Current sensor W
43 Resistor 44 Amplifier circuit (full range)
45 Amplifier circuit (enlarge)
46 A / D converter 47 Processor 51 Load U
52 Load W
8 lines

Claims (8)

A secondary battery is connected to the grid and is provided between the fuel cell, the power conversion device that controls the fuel cell, the power conversion device and the grid, and obtains a secondary current corresponding to the primary current flowing through the main trunk of the grid. A fuel cell device comprising a current sensor and an internal load,
Obtaining a first measurement value corresponding to the secondary current when the internal load is in a stopped state;
Obtaining a second measurement value corresponding to the secondary current when the internal load is in operation;
Calculating a difference between the first measurement value and the second measurement value as a third measurement value;
A control unit that converts the secondary current into the primary current based on the third measurement value and a current flowing through the internal load when the internal load is in an operating state ;
A fuel cell device in which a current flowing through the internal load is known when the internal load is in an operating state . The controller is
Set the determination range according to the current flowing through the internal load,
When the third measurement value is within the determination range, determine a current conversion coefficient for converting the secondary current into the primary current;
2. The fuel cell device according to claim 1, wherein when the third measurement value is outside the determination range, information indicating that the current conversion coefficient cannot be determined is output.   The fuel cell device according to claim 1, wherein the internal load is an auxiliary machine of the fuel cell device. The controller is
Using the temporary current conversion coefficient set automatically or manually, the first measured value and the second measured value are converted into the first temporary current value and the second temporary current value, respectively.
4. The fuel cell device according to claim 1, wherein the provisional current conversion coefficient is changed based on a difference between the first provisional current value and the second provisional current value. 5. The controller is
Using the temporary current conversion coefficient set automatically or manually, the first measured value and the second measured value are converted into the first temporary current value and the second temporary current value, respectively.
Based on the difference between the first temporary current value and the second temporary current value, a current conversion coefficient for converting the secondary current into the primary current is determined, or the current conversion coefficient cannot be determined. The fuel cell device according to any one of claims 1 to 3, which outputs information. The controller is
Outputting a current conversion coefficient for converting the secondary current into the primary current, determined based on the third measurement value and a current flowing through the internal load when the internal load is in an operating state; The fuel cell device according to any one of claims 1 to 3, which receives a confirmation input as to whether or not the conversion coefficient is correct. The controller is
Calculating at least two third measurement values by repeating the process of acquiring the first measurement value, the process of acquiring the second measurement value, and the process of calculating the third measurement value at least twice;
The fuel cell device according to any one of claims 1 to 6, wherein a current conversion coefficient for converting the secondary current into the primary current is determined based on the at least two third measurement values. A secondary battery is connected to the grid and is provided between the fuel cell, the power conversion device that controls the fuel cell, the power conversion device and the grid, and obtains a secondary current corresponding to the primary current flowing through the main trunk of the grid. A control method of a fuel cell device comprising a current sensor that performs an internal load,
Obtaining a first measurement value corresponding to the secondary current when the internal load is in a stopped state;
Obtaining a second measurement value corresponding to the secondary current when the internal load is in operation;
Calculating a difference between the first measurement value and the second measurement value as a third measurement value;
Wherein the third measurement value, the internal load is based on the current flowing through the internal load when the operating condition, viewed including the steps of converting the secondary current in the primary current,
A control method of a fuel cell device , wherein a current flowing through the internal load is known when the internal load is in an operating state .

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