JP4517500B2 - Fuel cell device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel cell device and a control method for the fuel cell device.
[0002]
[Prior art]
Conventionally, since fuel cells have high power generation efficiency and do not emit harmful substances, they have been put into practical use as power generators for industrial and household use, or as power sources for artificial satellites and spacecrafts. Development is progressing as a power source for vehicles such as buses and trucks.
[0003]
The vehicle is equipped with a large number of auxiliary devices that consume electricity even when the vehicle is stopped, such as a lighting device, a radio, and a power window. Since the output range is extremely wide, when the fuel cell is used as a power source for a vehicle, it is common to use a hybrid in which a battery (storage battery or secondary battery) is used in combination.
[0004]
FIG. 2 shows a conventional fuel cell device.
[0005]
In the figure, 101 is a fuel cell, such as alkaline aqueous solution type (AFC), phosphoric acid type (PAFC), molten carbonate type (MCFC), solid oxide type (SOFC), direct type methanol (DMFC), etc. Although there may be, a polymer electrolyte fuel cell (PEMFC) is common.
[0006]
Reference numeral 102 denotes a battery that can be repeatedly discharged by charging, and is generally a lead storage battery, a nickel cadmium battery, a nickel metal hydride battery, a lithium ion battery, a sodium sulfur battery, or the like.
[0007]
Further, 103 is an inverter (INV) which converts a direct current from the fuel cell 101 or the battery 102 into an alternating current and supplies the alternating current to an unillustrated alternating current motor which is a driving source for rotating the wheels of the vehicle. When the drive source is a DC motor, the DC current from the fuel cell 101 or the battery 102 is directly supplied to the drive source without going through the inverter 103.
[0008]
In the fuel cell device having the above-described configuration, the fuel cell 101 and the battery 102 are connected in parallel to supply current to the inverter 103. For example, when the vehicle is stopped, the fuel cell 101 Is stopped, and when the current from the fuel cell 101 alone does not satisfy the required current during high load operation such as on a slope, the current is automatically supplied from the battery 102 to the inverter 103.
[0009]
In addition, when the AC motor as the drive source functions as a power generator during the deceleration operation of the vehicle and generates a so-called regenerative current, the regenerative current is supplied to the battery 102 during the deceleration operation of the vehicle. Will be recharged. Further, even when the regenerative current is not supplied, the current generated by the fuel cell 101 is automatically supplied to the battery 102 when the battery 102 is discharged and the terminal voltage decreases.
[0010]
As described above, in the fuel cell device, when the battery 102 is always charged and the current from the fuel cell 101 alone does not satisfy the required current, the current is automatically supplied from the battery 102 to the inverter 103. Since the vehicle is supplied, the vehicle can travel stably in various travel modes.
[0011]
[Problems to be solved by the invention]
However, in the conventional fuel cell device, only the fuel cell 101 and the battery 102 are connected in parallel, and the distribution state of the current flowing through the fuel cell 101 and the battery 102 is not controlled at all. Depending on the current-voltage characteristics of the fuel cell 101 and the battery 102, the amount of current flowing through each of them is determined.
[0012]
FIG. 3 is a diagram showing characteristics of a fuel cell and a battery in a conventional fuel cell circuit. In the figure, the horizontal axis represents current, and the vertical axis represents voltage and power.
[0013]
In the figure, 105 is a curve showing the voltage-current characteristics of the fuel cell 101 (FIG. 2), 106 is a curve showing the voltage-current characteristics of the battery 102, 107 is the original voltage when the fuel cell 101 and the battery 102 are summed up. A curve indicating current characteristics, and 108 is a curve indicating the original power characteristics when the fuel cell 101 and the battery 102 are summed.
[0014]
For example, during a constant load operation of the vehicle, since the required current is satisfied only by the current from the fuel cell 101, the curve 106 is originally not required to be supplied from the battery 102 to the inverter 103. As shown, the battery 102 starts to output from the low current region, so that current is also supplied from the battery 102 to the inverter 103. As described above, since current always flows from the battery 102, it is necessary to increase the capacity of the battery 102. In general, however, the battery is large, heavy, and expensive. Increasing the capacity of 102 increases the volume and weight of the vehicle and increases the cost.
[0015]
Further, when the terminal voltages of the fuel cell 101 and the battery 102 are set so that the voltage difference between the two becomes small, even when the battery 102 is discharged and the terminal voltage decreases, the curve 106 becomes As shown, the current from the fuel cell 101 hardly flows to the battery 102, and it takes time to charge the battery 102. For this reason, the travel of the vehicle is restricted, and in the worst case, the battery 102 rises as shown by the curve 106.
[0016]
On the contrary, if the voltage difference is set to be large, a large current flows from the fuel cell 101 to the battery 102, so that the battery 102 is destroyed by being overcharged.
[0017]
Further, since the voltage-current characteristic of the battery usually varies depending on the remaining capacity, the output distribution of the fuel cell 101 and the battery 102 is maintained in a predetermined state, and the fuel cell 101 and the battery as shown by the curves 107 and 108 are obtained. It is difficult to exhibit the original current-voltage characteristic or power characteristic when 102 is totaled. Therefore, even when the current from the fuel cell 101 alone does not satisfy the required current, such as during a high-load operation on a hill or the like, the vehicle 102 is restricted from traveling without being supplied with current from the battery 102 to the inverter 103. In addition, even if the remaining capacity of the battery 102 decreases, the battery 102 rises without current being supplied from the fuel cell 101.
[0018]
The present invention solves the problems of the conventional fuel cell device, appropriately controls the distribution state of the current flowing through the fuel cell and the battery, and appropriately charges the battery without increasing the capacity of the battery. It is another object of the present invention to provide a fuel cell device and a control method for the fuel cell device that can maintain the output distribution of the fuel cell and the battery in a predetermined state.
[0019]
[Means for Solving the Problems]
For this purpose, the fuel cell device of the present invention includes a fuel cell, a load connected to the output terminal of the fuel cell, and a storage means circuit connected in parallel to the fuel cell with respect to the load. In the fuel cell device, the power storage means circuit supplies power storage means, a booster circuit that boosts the output voltage of the power storage means and supplies current to the load, and supplies current output from the fuel cell to the power storage means. Charging circuit for charging the power storage means, Based on vehicle speed and accelerator opening Vehicle running mode Detecting traveling mode Detecting means, and the traveling mode The travel of the vehicle detected by the detecting means mode In response to the, In order for the SOC of the power storage means to be within the range of the reference value set corresponding to the driving mode, The booster circuit and the charging circuit are selectively operated.
[0022]
In another fuel cell device of the present invention, a fuel cell connected to a load, a storage means circuit connected in parallel to the fuel cell and the load, and a current from the storage means circuit is the fuel cell In the fuel cell device including a diode element disposed so as not to be supplied to the battery, the power storage circuit includes a charging switching element and a boosting switching element connected in series to each other, and the boosting switching element. Power storage means connected in parallel via a reactor, Based on vehicle speed and accelerator opening Vehicle running mode Detecting traveling mode Detecting means, and the traveling mode The travel of the vehicle detected by the detecting means mode In response to the, In order for the SOC of the power storage means to be within the range of the reference value set corresponding to the driving mode, The charging switching element and the boosting switching element are selectively operated.
[0023]
In still another fuel cell device of the present invention, the load is a drive control device for a drive motor that drives the vehicle.
[0026]
In still another fuel cell device of the present invention, the power storage means is a circuit including a secondary battery and a capacitor.
[0027]
In still another fuel cell device of the present invention, the power storage means is a capacitor.
[0028]
In still another fuel cell device of the present invention, the power storage means is a secondary battery.
[0037]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0038]
FIG. 1 is a conceptual diagram of a fuel cell device according to an embodiment of the present invention, and FIG. 4 is a diagram showing an example in which a battery and an electric double layer capacitor are combined and used as power storage means.
[0039]
In FIG. 1, reference numeral 10 denotes a fuel cell (FC) circuit, which is used as a power source for vehicles such as passenger cars, buses, and trucks. Here, the vehicle includes a large number of auxiliary devices that consume electricity even when the vehicle is stopped, such as a lighting device, a radio, and a power window. Since the required output range is extremely wide, the fuel cell 11 as the power source and the battery 12 as the power storage means are used in combination.
[0040]
The fuel cell 11 may be of an alkaline aqueous solution type (AFC), phosphoric acid type (PAFC), molten carbonate type (MCFC), solid oxide type (SOFC), direct methanol (DMFC), or the like. A solid polymer type fuel cell (PEMFC) is preferable.
[0041]
It is more desirable to use a PEMFC (proton exchange fuel cell) type fuel cell or a PEM (proton exchange membrane) type fuel cell that uses hydrogen as a fuel and oxygen or air as an oxidant. Here, the PEM type fuel cell is generally a stack in which a plurality of cells (fuel cells) in which a catalyst, an electrode, and a separator are combined on both sides of a polymer membrane that transmits ions such as protons are connected in series. (See JP-A-11-317236, etc.).
[0042]
For example, in the present embodiment, as an example, a PEM type fuel cell is used, and a stack in which 400 cells are connected in series is used. In this case, the total electrode area is 300 cm. ² The open terminal voltage is about 350 [V], and the output is about 50 [kW]. And the temperature at the time of a steady operation is about 50-90 [degreeC].
[0043]
Hydrogen, which is fuel, can be supplied directly to the fuel cell by reforming methanol, gasoline, etc. with a reformer (not shown), but is stable and sufficient even when the vehicle is operated at high loads. In order to be able to supply an amount of hydrogen, it is desirable to supply hydrogen stored in a hydrogen storage alloy, a hydrogen gas cylinder or the like. As a result, hydrogen is always sufficiently supplied at a substantially constant pressure, so that the fuel cell 11 can follow the fluctuation of the vehicle load without delay and supply the necessary current.
[0044]
In this case, the output impedance of the fuel cell 11 is extremely low and can be approximated to zero.
[0045]
Reference numeral 12 denotes a secondary battery as a power storage means that can be repeatedly discharged by charging, that is, a battery (storage battery), such as a lead storage battery, a nickel cadmium battery, a nickel hydrogen battery, a lithium ion battery, or a sodium sulfur battery. However, high-performance lead-acid batteries, lithium-ion batteries, sodium-sulfur batteries, etc. used for electric vehicles are desirable.
[0046]
For example, in this embodiment, a high performance lead acid battery is used as an example.
In this case, the open terminal voltage is about 210 [V], and has a capacity capable of supplying about 10 [kW] of power for about 5 to 20 minutes.
[0047]
The power storage means does not necessarily have to be a battery, and electrically stores and discharges energy, such as a capacitor (capacitor) such as an electric double layer capacitor, a flywheel, a superconducting coil, and a storable pressure device. Any form may be used as long as it has a function. Furthermore, any of these may be used alone, or a plurality of them may be used in combination.
[0048]
For example, as described in Japanese Patent No. 2753907, a battery and an electric double layer capacitor can be combined and used as the livestock power means. In this case, as shown in FIG. 4, the battery Bt is connected in series with the capacitor C <b> 2 in the power storage means 12 ′. The positive terminal of the battery Bt is connected to the negative terminal of the capacitor C2, and is connected to the collector electrode of the transistor Tr1 and the emitter electrode of the transistor Tr2.
[0049]
The emitter electrode of the transistor Tr1 and the collector electrode of the transistor Tr2 are connected to the positive terminal of the capacitor C2 and the collector electrode of the transistor Tr3. A diode D1 is connected between the emitter and collector electrodes of the transistor Tr3.
[0050]
Further, the positive terminal of the capacitor C1 is connected to the emitter electrode of the transistor Tr3. Thus, the capacitor C1 is connected in parallel to the battery Bt via the transistors Tr1 to Tr3 and the diode D1.
[0051]
Here, the battery Bt is the same as the battery 12, and the capacitors C1 and C2 have a large capacity per unit volume like an electric double layer capacitor, and have a large capacity with a low resistance and a high output density. It is desirable to be. The capacities of the capacitors C1 and C2 can be appropriately determined in consideration of the balance with the occupied volume. For example, the capacity is preferably 9F or more.
[0052]
The capacitors C1 and C2 may each be a plurality of capacitors connected in series. In this case, the withstand voltage of each capacitor can be set low.
[0053]
The positive terminal of the livestock storage means 12 'is connected to the positive terminal of the capacitor C2 and the collector electrode of the transistor Tr3, and the negative terminal of the livestock storage means 12' is connected to the battery Bt. The negative electrode of the capacitor C1 and the negative electrode of the capacitor C1 are connected.
[0054]
In the livestock charging means 12 'having such a configuration, the transistors Tr1 to Tr3 are switched to control the output current from the battery Bt and the capacitors C1 and C2, and the charging current to the battery Bt and the capacitors C1 and C2 Also comes to control.
[0055]
Next, in FIG. 1, 13 is an inverter device which is a drive control device as a load, which converts a direct current from the fuel cell 11 or the battery 12 into an alternating current and rotates a vehicle wheel as a drive motor. The motor 14 is supplied. Here, the motor 14 also functions as a generator, and generates a so-called regenerative current when the vehicle is decelerated. In this case, since the motor 14 is rotated by the wheel to generate electric power, the wheel is braked, that is, functions as a vehicle braking device (brake). Then, as will be described later, the regenerative current is supplied to the battery 12 to charge the battery 12.
[0056]
Reference numeral 15 denotes a battery charge control circuit, which is a parallel circuit of an IGBT (insulated gate bipolar transistor) 15a, which is a high-speed switching element as a charging switching element, and a thyristor 15b. Here, the IGBT 15a allows a current of about 200 [A].
[0057]
On the other hand, 16 is a battery discharge control circuit as a step-up control circuit, and is a parallel circuit of an IGBT 16a and a thyristor 16b as a step-up switching element, like the battery charge control circuit. Here, the IGBT 16a allows a current of about 200 [A].
[0058]
Reference numeral 17 denotes a reactor that allows a current of about 200 [A], and constitutes a booster circuit together with the battery discharge control circuit 16 to boost the output voltage of the battery 12.
[0059]
Here, the IGBT 16a in the battery discharge control circuit 16 is turned on and off by a switching signal having a predetermined period (for example, about 20 [kHz]). When the IGBT 16a is turned on, a direct current output from the battery 12 flows to the reactor 17 and energy is accumulated. When the IGBT 16a is turned off, a voltage corresponding to the energy accumulated in the reactor 17 is The voltage is boosted by adding to the output voltage of the battery 12. The boosted output voltage of the battery 12 can be adjusted as appropriate by the switching signal, but is adjusted to a level slightly higher than the output voltage of the fuel cell 11.
[0060]
In the thyristor 16b in the battery discharge control circuit 16, the insulation between the emitter and the collector is broken by the back electromotive force generated between the emitter and the collector of the IGBT 16a when the IGBT 16a is turned off. To prevent it.
[0061]
Reference numeral 18 denotes a current sensor for measuring a current value flowing through the circuit, and reference numeral 19 denotes a thyristor as a diode element disposed so that current from a load or a secondary battery is not supplied to the fuel cell.
[0062]
Reference numeral 20 denotes a hybrid circuit electronic control unit, which includes an arithmetic means such as a CPU, a storage means such as a semiconductor memory, an input / output interface, etc., and measures the current value, voltage value, etc. in the fuel cell circuit 10, and The operation of the battery charge control circuit 15 and the battery discharge control circuit 16 is controlled. Further, the hybrid circuit electronic control unit 20 is communicably connected to other sensors in the vehicle and other control devices such as a vehicle electronic control unit 21, a fuel cell electronic control unit 22, and an ignition control device 24, which will be described later. The operation of the fuel cell circuit 10 is comprehensively controlled in cooperation with other sensors and other control devices.
[0063]
The hybrid circuit electronic control unit 20 may exist independently, for example, may exist as a part of another control device such as the vehicle electronic control unit 21.
[0064]
Here, for example, in the present embodiment, the hybrid circuit electronic control unit 20 includes an input / output interface with two current sensors 18, two input / output interfaces for voltage measurement, and an input for the battery charge control circuit 15. An output interface, an input / output interface for the battery discharge control circuit 16, an input / output interface for the vehicle electronic control unit 21, an input / output interface for the fuel cell electronic control unit 22, and an input / output interface for the ignition control device 24 are provided. . The hybrid circuit electronic control unit 20 also includes a power interface connected to a power battery 23 as a power source.
[0065]
Next, the vehicle electronic control unit 21 includes a calculation means such as a CPU, a storage means such as a semiconductor memory, an input / output interface, and the like, and detects a vehicle speed, an air temperature, an accelerator opening, etc. The overall operation of the vehicle including it is controlled. The accelerator opening is detected by the degree of depression of an accelerator pedal (throttle pedal) in a general vehicle, but as a means for controlling the output and speed of the vehicle, a rotary accelerator grip is used instead of the accelerator pedal. When an accelerator controller such as a joystick, a bar handle, or a rotary dial is used, it is detected by the degree of movement of these accelerator controllers.
[0066]
The fuel cell electronic control unit 22 includes a calculation means such as a CPU, a storage means such as a semiconductor memory, an input / output interface, and the like, and a flow rate of hydrogen, oxygen, air, etc. supplied to the fuel cell 11, temperature, and output voltage. Etc. are detected to control the operation of the fuel cell 11.
[0067]
The power battery 23 is composed of a battery such as a lead storage battery, a nickel cadmium battery, a nickel hydride battery, a lithium ion battery, or a sodium sulfur battery that can be repeatedly discharged by charging, and a DC current of 12 [V] is supplied to the hybrid battery. This is supplied to the circuit electronic control unit 20. The power supply battery 23 may supply a direct current as a power source to auxiliary equipment such as a vehicle radio and a power window.
[0068]
The ignition control device 24 is a device for starting the fuel cell circuit. When the vehicle driver turns on the switch, the ignition control device 24 transmits the signal to the hybrid circuit electronic control unit 20 and other devices.
[0069]
Next, the operation of the fuel cell apparatus having the above configuration will be described.
[0070]
FIG. 5 is a diagram showing characteristics of the fuel cell and the battery in the embodiment of the present invention. In FIG. 5, the horizontal axis represents current I, and the vertical axis represents voltage V and power kW.
[0071]
In FIG. 5, 41 is a curve showing the voltage-current characteristics of the fuel cell 11 (FIG. 1). The curve 41 showing the voltage-current characteristic of the fuel cell 11 is a downward-sloping curve in which the voltage decreases as the current increases as a whole, as in the case of a normal PEM type fuel cell. The slope is gentle until the current value A, but the slope becomes steep with the point B corresponding to the current value A as an inflection point. The corresponding power characteristic of the fuel cell 11 is indicated by a curve 45.
[0072]
From this, it can be seen that it is efficient to use the fuel cell 11 in the range up to the vicinity of the current value A. As described above, the fuel cell 11 is a power source having an output impedance of almost zero.
[0073]
On the other hand, the curve 43 indicating the voltage-current characteristics of the battery 12 is a straight line with a downward slope in which the voltage decreases as the current increases as a whole, as in the case of a normal battery, and exceeds the current value A. There is no change. Moreover, the inclination angle is substantially equal to the inclination angle of the curve 41 up to the current value A.
[0074]
Therefore, in the range where the current to be supplied to the motor 14 via the inverter 13, that is, the value of the required current is up to the current value A, the current is supplied only from the fuel cell 11, and the value of the required current is the current value A. It can be seen that it is sufficient to supply the current from the battery 12 in addition to the current from the fuel cell 11 in the range above or near. Since the open terminal voltage of the battery 12 is approximately equal to the terminal voltage of the fuel cell 11 at the point B on the curve 41 corresponding to the current value A, the required current value is the current value. In the range up to the vicinity of A, no current is supplied from the battery 12.
[0075]
However, when the output voltage of the battery 12 is boosted to the terminal voltage of the fuel cell 11 by a booster circuit, current is also actively supplied from the battery 12.
[0076]
Since the terminal voltage of the fuel cell 11 at the point B on the curve 41 corresponding to the current value A corresponding to the current value A is substantially equal to the open circuit voltage of the battery 12, the current value A is slightly exceeded. In the range, current is also supplied from the battery 12. However, when current is also supplied from the battery 12, the terminal voltage of the battery 12 decreases, as can be seen from the curve 43 indicating the voltage-current characteristics of the battery 12, so that the current value is much lower. It will not rise.
[0077]
However, when the booster circuit boosts the output voltage of the battery 12 to the terminal voltage of the fuel cell 11 and the currents from the fuel cell 11 and the battery 12 are combined, a curve indicating the voltage-current characteristics. 42. As a whole, the current increases as the current decreases and the voltage decreases. The corresponding power characteristic is indicated by a curve 44.
[0078]
Here, for example, if the power to be supplied to the motor 14 via the inverter 13, that is, the required power is C, this corresponds to a point D on the curve 44 indicating the power characteristics. It can be seen that the point on the curve 42 indicating the voltage-current characteristic corresponding to the point D is E, and the current value corresponding to this is F. Therefore, in this case, it is understood that the fuel cell 11 may supply a current having a current value A, and the battery 12 may supply a current having a current value (FA).
[0079]
In the present embodiment, the characteristics of the fuel cell 11 and the battery 12 as shown in FIG. 5 are stored in advance in the storage means of the hybrid circuit electronic control unit 20. Then, based on signals such as the vehicle speed of the vehicle and the accelerator opening transmitted from the vehicle electronic control unit 21, the required power to be supplied to the motor 14 is calculated by the calculation means, and the required current corresponding to the required power is calculated. The value is found based on the characteristics of the fuel cell 11 and the battery 12 as shown in FIG.
[0080]
On the other hand, as will be described later, the fuel cell 11 and the fuel cell 11 are determined so that the traveling mode of the vehicle is determined, the generation of the regenerative current is predicted based on the traveling mode, and the regenerative current can be charged to the battery 12. Although the output current from the battery 12 is controlled, the output current is also controlled based on the characteristics of the fuel cell 11 and the battery 12 as shown in FIG.
[0081]
Therefore, here, the basic operation of the fuel cell circuit 10 based on the characteristics of the fuel cell 11 and the battery 12 as shown in FIG. 5 will be described.
[0082]
First, in the case where the value of the required current is equal to or less than the current value A in FIG. 5 and when the current is supplied only from the fuel cell 11, the IGBTs 15a and 16a in the battery charge control circuit 15 and the battery discharge control circuit 16 are Turn off.
[0083]
In this case, the fuel cell 11 is always sufficiently supplied with hydrogen as the fuel and oxygen or air as the oxidant, so that even if the value of the required current fluctuates, the fuel cell 11 Is automatically supplied with a current corresponding to the required current value. Therefore, it is not necessary to control the output current of the fuel cell 11 in accordance with the fluctuation of the required current value. Note that the value of the current supplied from the fuel cell 11 is measured by the current sensor 18, and the hybrid circuit electronic control unit 20 always detects whether or not it is equal to or less than the current value A. Further, the voltage is always detected by the hybrid circuit electronic control unit 20.
[0084]
Next, when the required current value or the current value measured by the current sensor 18 is equal to or greater than the current value A, for example, when the current value F in FIG. When the IGBT 16a in 16 is kept in the OFF state, the current value from the battery 12 does not increase so much as described above.
[0085]
Here, in order to actively supply current from the battery 12 as well, the hybrid circuit electronic control unit 20 causes the IGBT 16a in the battery discharge control circuit 16 to have a predetermined period (for example, about 20 kHz). Turns on and off by switching signal. When the IGBT 16a is turned on, the DC current output from the battery 12 flows to the reactor 17 and energy is accumulated. When the IGBT 16a is turned off, a voltage corresponding to the energy accumulated in the reactor 17 is The sum is added to the output voltage of the battery 12, and the sum is substantially equal to the output voltage of the fuel cell 11. This corresponds to the point G on the curve 43 in FIG. 5 being shifted upward to the point E on the curve 42.
[0086]
A current having a voltage value corresponding to the point E and a current value (FA) is supplied from the battery 12 to the motor 14 via the inverter 13. The value of the current supplied from the battery 12 is measured by the current sensor 18 and checked by the hybrid circuit electronic control unit 20.
[0087]
Next, the basic operation of the fuel cell circuit 10 when the battery 12 is charged will be described because the SOC (state of charge) of the battery 12 has decreased.
[0088]
First, when the vehicle is decelerated, the motor 14 functions as a generator to generate an AC regenerative current. Subsequently, the AC regenerative current is converted into a DC regenerative current by the inverter 13. At this time, the hybrid circuit electronic control unit 20 turns on the IGBT 15a in the battery charge control circuit 15 by a switching signal. Therefore, since the DC regenerative current is supplied to the battery 12 through the IGBT 15a, the battery 12 is charged.
[0089]
The value of the regenerative current is measured by the current sensor 18 and is constantly checked by the hybrid circuit electronic control unit 20. Also, the voltage is always checked by the hybrid circuit electronic control unit 20. When the SOC of the battery 12 is sufficiently increased, the IGBT 15a is turned off. Further, when the value of the regenerative current is excessive, the IGBT 15a is turned on / off by a switching signal having a predetermined period to control the value of the current flowing through the IGBT 15a.
[0090]
Therefore, when the SOC of the battery 12 is sufficiently high, the battery 12 is not charged or a large current is not supplied to the battery 12, so that the battery 12 is not destroyed by being overcharged. .
[0091]
Further, when the SOC of the battery 12 is lowered and charging is required, and the regenerative current is not generated, the battery 12 is charged by supplying current from the fuel cell 11. In this case, the hybrid circuit electronic control unit 20 turns on the IGBT 15a in the battery charge control circuit 15 by a switching signal, so that a DC regenerative current is supplied to the battery 12 through the IGBT 15a. Therefore, the battery 12 is charged.
[0092]
The value of the current from the fuel cell 11 and the value of the current supplied to the battery 12 are measured by a current sensor 18 and are constantly checked by the hybrid circuit electronic control unit 20. Also, the voltage is always checked by the hybrid circuit electronic control unit 20. Then, when the SOC of the battery 12 is sufficiently increased, when the value of the current supplied from the fuel cell 11 becomes the current value A, and the required current supplied to the motor 14 via the inverter 13 When the value of is large, the IGBT 15a is turned off. When the value of the current supplied to the battery 12 is excessive, the IGBT 15a is turned on / off by a switching signal having a predetermined period to control the value of the current flowing through the IGBT 15a.
[0093]
Therefore, when the SOC of the battery 12 is sufficiently high, the battery 12 is not charged or a large current is not supplied to the battery 12, so that the battery 12 is not destroyed by being overcharged. . Moreover, an excessive load is not applied to the fuel cell 11 and the required current cannot be dealt with.
[0094]
Next, an example of the relationship between the operation of the fuel cell circuit 10 described above and the travel mode as the travel state of the vehicle will be described.
[0095]
FIG. 6 is a diagram showing an example of the relationship between the operation of the fuel cell circuit 10 and the travel mode in the embodiment of the present invention. In FIG. 6, the horizontal axis represents the vehicle load and the vertical axis represents the output.
[0096]
In FIG. 6, 51 is a straight line showing the relationship between the vehicle load and the output of the fuel cell 11 (FIG. 1) and the battery 12, that is, the required current, when the vehicle load is positive, and 52 is the vehicle load. It is a straight line showing the relationship between the vehicle load and the output of the motor 14 in the negative range, that is, the magnitude of the regenerative current.
[0097]
Here, the load of the vehicle is the lowest when the driving mode of the vehicle is a low-load driving that travels in an urban area, etc., a high-speed cruise that travels on a highway, a high-load driving that travels uphill, etc. It becomes higher in order of maximum load driving on a slope. The value of the required current increases in proportion to the vehicle load.
[0098]
On the other hand, when the vehicle is traveling downhill or the like and the regeneration is a traveling mode in which the motor 14 functions as a generator to generate a regenerative current, the vehicle load is negative because the vehicle is decelerating. The value of the regenerative current is proportional to the absolute value of the vehicle load.
[0099]
In the region 53 where the vehicle load is negative, the hybrid circuit electronic control unit 20 turns on the IGBT 15a in the battery charge control circuit 15 by a switching signal, so that the regenerative current is supplied to the battery 12 through the IGBT 15a. Is done. Therefore, the battery 12 is charged.
[0100]
Next, in the region 54 from 0 to the boundary J corresponding to the current value A in FIG. 5 through the inverter 13 to which the current corresponding to the required current is automatically supplied from the fuel cell 11 in the region 54. To the motor 14.
[0101]
In the region 54, when the SOC of the battery 12 is low, the hybrid circuit electronic control unit 20 removes the fuel cell 11 from the fuel cell 11 by turning on the IGBT 15a in the battery charge control circuit 15 for an appropriate time. A current is supplied to charge the battery 12.
[0102]
On the contrary, when the SOC of the battery 12 is high and there is no room for accepting the regenerative current, it is desirable to discharge the battery 12 slightly in order to generate room for accepting the regenerative current. The hybrid circuit electronic control unit 20 turns on and off the IGBT 16 a in the battery discharge control circuit 16 by a switching signal having a predetermined period so that the current from the battery 12 is also supplied to the motor 14 via the inverter 13. Thereby, since the electric current which should be supplied from the said fuel cell 11 can be reduced, the load of the said fuel cell 11 is reduced and the consumption of fuel can be suppressed. The SOC of the battery 12 is preferably about 80%.
[0103]
Finally, in the regions 55 and 56 where the vehicle load exceeds the boundary J, the value of the required current exceeds the current value A in FIG. 5, so the hybrid circuit electronic control unit 20 is connected to the battery discharge control circuit 16. The IGBT 16 a is turned on / off by a switching signal of a predetermined period, and in addition to the current of the current value A from the fuel cell 11, a current exceeding the current value A is supplied from the battery 12 to the motor 14 via the inverter 13. To be. In FIG. 6, a region 55 indicates a range of output due to current from the fuel cell 11, and a region 56 indicates a range of output due to current from the battery 12.
[0104]
Next, the control method of the fuel cell circuit 10 corresponding to various driving modes of the vehicle in the present embodiment will be described in detail.
[0105]
FIG. 7 is a diagram showing a basic concept of a control method for a fuel cell circuit according to an embodiment of the present invention, FIG. 8 is a diagram showing a SOC value of a battery in various travel modes according to an embodiment of the present invention, and FIG. FIG. 10 is a diagram showing the output ranges of the fuel cell and the battery in various travel modes in the embodiment of the present invention, FIG. 10 is a flowchart showing the control operation of the fuel cell circuit in the embodiment of the present invention, and FIG. FIG. 12 is a second flowchart showing the operation of the SOC out-of-range processing in the embodiment of the present invention, and FIG. 13 is the embodiment of the present invention. 10 is a third flowchart showing the operation of the SOC out-of-range process in FIG.
[0106]
In the present embodiment, the fuel cell circuit 10 (FIG. 1) is controlled so that the regenerative current can be used as much as possible without wasting it. That is, the regenerative current is energy that is generated as a result of causing the motor 14 to function as a brake when it is necessary to brake the vehicle as when traveling downhill or the like, and this is used. As a result, the fuel of the fuel cell 11 can be saved.
[0107]
Since the regenerative current is not constantly generated, in order to use the regenerative current, it is necessary to charge the battery 12 first. Therefore, when the SOC of the battery 12 is high, it is necessary to leave a room where the SOC can be charged by lowering the SOC to some extent. On the other hand, when the vehicle travels in the regions 55 and 56 where the vehicle load exceeds the boundary J in FIG. 6, it is necessary to output current from the battery 12. Therefore, if the SOC is too low, high load operation and maximum load operation are performed. It will not be possible to cope with the case of continuous.
[0108]
Therefore, it is necessary to control the SOC of the battery 12 so that the generation of the regenerative current can be predicted based on the traveling mode of the vehicle and the regenerative current can be charged to the battery 12.
[0109]
Next, the basic concept of the driving mode of the vehicle and the outputs of the fuel cell 11 and the battery (BT) 12 will be described.
[0110]
FIG. 7 shows a table for determining the driving mode of the vehicle depending on which region is operated in a predetermined time (5 to 20 minutes). Here, 65 is a curve showing the relationship between the output of the motor 14 and the speed of the vehicle when running on a flat road with a gradient of 0 degrees at a constant speed, that is, when running at a constant speed.
[0111]
First, since the vehicle speed is low in the region 61 and the output of the motor 14 is higher than the constant speed running, it can be said that the region 61 is a running mode that repeats start and stop in an urban area, that is, an urban area mode. Therefore, since there are many deceleration operations that brake the vehicle and a regenerative current is expected to occur frequently, the current of the battery 12 is mainly supplied so that the SOC of the battery 12 is relatively low, for example, 60 [ %] So that the battery 12 can be charged when a regenerative current is generated.
[0112]
The region 62 has a high vehicle speed, and the output of the motor 14 is higher than that of the constant speed traveling. Therefore, it can be said that the region 62 is a traveling mode for cruising on the suburbs and highways, that is, a high speed mode. Therefore, since the deceleration operation for braking the vehicle is small and the regenerative current is not generated so much, on the other hand, it may be predicted that the required current may not be satisfied only by the current from the fuel cell 11. Is maintained at a high level, for example, about 75 [%], so that current can be supplied from the battery 12 whenever necessary.
[0113]
Next, since the output of the motor 14 is higher than the constant speed running, the region 63 can be said to be a running mode in which a downhill is taken on a mountain road, that is, a mountain road lower mode. Therefore, although it is required to output on an uphill occasionally, since a high regenerative current is expected to occur, the SOC of the battery 12 is kept low, for example, about 50 [%], and the regenerative current is maintained. So that the battery 12 can be fully charged.
[0114]
Finally, since the output of the motor 14 is high even in a region where the vehicle speed is low, it can be said that the region 64 is a traveling mode that climbs uphill on a mountain road, that is, a mountain road top mode. Therefore, although a regenerative current is generated on the occasional downhill, since it is predicted that the required current cannot be satisfied only by the current from the fuel cell 11, the SOC of the battery 12 is relatively high, for example, 70 [% The current can be supplied also from the battery 12 while maintaining the level.
[0115]
In the present embodiment, the SOC reference value of battery 12 is set according to the determined travel mode. Then, the operation of the fuel cell circuit 10 is controlled so that the actual measured value of the SOC of the battery 12 is within the range of the reference value.
[0116]
First, the hybrid circuit electronic control unit 20 determines the vehicle speed of the past 5 to 20 minutes, the accelerator opening θ (proportional to the torque to be generated by the motor 14), the current value supplied from the fuel cell 11 and the battery 12, Based on a change in numerical values such as SOC and the duration, it is determined whether the traveling mode of the vehicle up to the present time is a high-speed mode, a mountain road mode, a mountain road mode, or a city area mode. Then, the operation of the fuel cell circuit 10 is controlled by predicting that the determined travel mode is continued for 5 to 20 minutes after the current time.
[0117]
Here, the time for determining the travel mode can be set as appropriate, and may be, for example, the past 1 to 5 minutes or the past 20 to 40 minutes. In addition, the time for which the determined travel mode is predicted to be continued can be set as appropriate. For example, it may be 1 to 5 minutes after the current time or 20 to 40 minutes after the current time.
[0118]
The numerical value is directly measured by the hybrid circuit electronic control unit 20 or measured by another control device such as the vehicle electronic control unit 21.
[0119]
Further, when the vehicle is provided with a vehicle position detection device, for example, a navigation device, the current travel mode of the vehicle can be determined by the navigation device. Therefore, the hybrid circuit electronic control unit 20 Based on the information from the navigation device, it may be determined whether the current driving mode of the vehicle is the high speed mode, the mountain road upper mode, the mountain road lower mode, or the urban area mode.
[0120]
Subsequently, as shown in FIG. 8, the hybrid circuit electronic control unit 20 sets the SOC reference value of the battery 12 according to the determined current vehicle travel mode.
[0121]
First, in the case of the high-speed mode, for example, a range of ± 10 [%] around 75 [%], that is, 65 to 85 [%] is set as the SOC reference value. In the case of the mountain road mode, for example, 60 to 80 [%], in the case of the mountain road mode, for example, 40 to 60 [%], and in the city area mode, for example, 50 to 70, for example. [%] Is set as the SOC reference value.
[0122]
Then, when the SOC of the battery 12 at the present time is within the range of the reference value, the operation of the fuel cell circuit 10 is controlled as shown in FIG.
[0123]
In the high speed mode shown in FIG. 9A, when the vehicle speed is low, current is supplied from the fuel cell 11 and current is not supplied from the battery 12, so that the battery charge control circuit 15 and the battery discharge control circuit are supplied. The IGBTs 15a and 16a in 16 are turned off. When the vehicle speed is high, current is also supplied from the battery 12 when the required power exceeds the supply capacity of the fuel cell 11. Also at this time, the IGBTs 15a and 16a in the battery charge control circuit 15 and the battery discharge control circuit 16 are turned off.
[0124]
Next, in the mountain road mode shown in FIG. 9B, when the vehicle speed is low and the accelerator opening θ is also small, current is supplied from the battery 12 and current is not supplied from the fuel cell 11. The IGBT 15a in the battery charge control circuit 15 is turned off, and the IGBT 16a in the battery discharge control circuit 16 is turned on / off by a switching signal having a predetermined cycle. As a result, the output voltage of the battery 12 is boosted and becomes equal to or higher than the output voltage of the fuel cell 11, so that no current is supplied from the fuel cell 11.
[0125]
Note that when the vehicle speed is low but the accelerator opening θ is large, the vehicle speed is the same as when the vehicle speed is low, and when the vehicle speed is high, the vehicle speed is the same as when the vehicle speed is high.
[0126]
Next, in the mountain road lower mode shown in FIG. 9C, the numerical ranges of the vehicle speed and the accelerator opening θ are different, but the others are the same as in the mountain road upper mode.
[0127]
Finally, in the urban mode shown in FIG. 9 (d), when the vehicle speed is low and the accelerator opening θ is large, only the current is supplied from the battery 12 and the current is not supplied from the fuel cell 11. Others are the same as those in the above-described mountain road mode or mountain road mode.
[0128]
Next, the operation of the fuel cell circuit 10 when the current SOC of the battery 12 is outside the range of the reference value will be described.
[0129]
First, when the SOC of the battery 12 does not reach the lower limit of the reference value range, the battery 12 needs to be charged. The current value is set.
[0130]
When the sum of the charging current and the required current does not exceed the maximum supply current value (current value A in FIG. 5) of the fuel cell 11, a part of the current supplied from the fuel cell 11 is the battery. Used for 12 charging. In this case, the IGBT 15a in the battery charge control circuit 15 is turned on.
[0131]
The current value from the fuel cell 11 and the current value of the charging current supplied to the battery 12 are measured by a current sensor 18 and are always detected by the hybrid circuit electronic control unit 20. Also, the voltage is always detected by the hybrid circuit electronic control unit 20. When the SOC of the battery 12 rises to the range of the reference value, when the value of the current supplied from the fuel cell 11 becomes the maximum supply current value, and through the inverter 13, the motor 14 When the value of the required current supplied to is large, the IGBT 15a is turned off. When the value of the current supplied to the battery 12 is excessive, the IGBT 15a is turned on / off by a switching signal having a predetermined period to control the value of the current flowing through the IGBT 15a.
[0132]
On the other hand, since the fuel cell 11 is not controlled at all, a current obtained by adding the charging current and the required current is supplied from the fuel cell 11.
[0133]
Next, when the sum of the charging current and the required current exceeds the maximum supply current value of the fuel cell 11, it is determined whether or not the required current exceeds the maximum supply current value of the fuel cell 11. .
[0134]
If not, charging of the battery 12 is stopped. In this case, the IGBT 15a in the battery charge control circuit 15 is turned off. Since the fuel cell 11 is not controlled at all, a current equal to the required current is supplied from the fuel cell 11 to the motor 14 via the inverter 13.
[0135]
Next, when the required current exceeds the maximum supply current value of the fuel cell 11, the charging of the battery 12 is stopped, and the current is also supplied from the battery 12 to the motor 14. . In this case, the IGBT 15a in the battery charge control circuit 15 is turned off, and the IGBT 16a in the battery discharge control circuit 16 is turned on / off by a switching signal having a predetermined cycle, thereby boosting the output voltage of the battery 12.
[0136]
The current value from the fuel cell 11 and the current value supplied from the battery 12 are measured by a current sensor 18 and are constantly checked by the hybrid circuit electronic control unit 20. Also, the voltage is always checked by the hybrid circuit electronic control unit 20. Then, the value of the current output from the battery 12 is controlled by controlling the on / off ratio (duty ratio) of the IGBT 16 a in the battery discharge control circuit 16.
[0137]
On the other hand, since the fuel cell 11 is not controlled at all, a current having a value obtained by subtracting the current from the battery 12 from the required current is supplied from the fuel cell 11.
[0138]
Next, when the SOC of the battery 12 exceeds the upper limit of the reference value range, it is determined whether or not the required current exceeds the maximum supply current value of the battery 12.
[0139]
If not, current is supplied from the battery 12 and current is not supplied from the fuel cell 11. In this case, the IGBT 15a in the battery charge control circuit 15 is turned off, and the IGBT 16a in the battery discharge control circuit 16 is turned on / off by a switching signal having a predetermined cycle, thereby boosting the output voltage of the battery 12.
[0140]
The value of the current supplied from the battery 12 is measured by the current sensor 18 and is always detected by the hybrid circuit electronic control unit 20. Also, the voltage is always detected by the hybrid circuit electronic control unit 20.
[0141]
On the other hand, although the fuel cell 11 is not controlled at all, no current is output from the fuel cell 11 because the boosted output voltage of the battery 12 is higher than the open terminal voltage of the fuel cell 11.
[0142]
Next, when the required current exceeds the maximum supply current value of the battery 12, a current value supplied from the battery 12 is set. Then, current is supplied from the fuel cell 11 and the battery 12 to the motor 14. In this case, the IGBT 15a in the battery charge control circuit 15 is turned off, and the IGBT 16a in the battery discharge control circuit 16 is turned on / off by a switching signal having a predetermined cycle, thereby boosting the output voltage of the battery 12.
[0143]
The current value from the fuel cell 11 and the current value supplied from the battery 12 are measured by a current sensor 18 and are always detected by the hybrid circuit electronic control unit 20. Also, the voltage is always detected by the hybrid circuit electronic control unit 20. Then, the on / off ratio of the IGBT 16 a in the battery discharge control circuit 16 is controlled to control the value of the current output from the battery 12.
[0144]
On the other hand, since the fuel cell 11 is not controlled at all, a current having a value obtained by subtracting the current from the battery 12 from the required current is supplied from the fuel cell 11.
[0145]
As described above, in the present embodiment, the reference value of the SOC of the battery 12 is set according to the determined traveling mode, and the fuel value is set so that the actual measured value of the SOC of the battery 12 is within the range of the reference value. The operation of the battery circuit 10 is controlled. Therefore, since the battery 12 has an appropriate room for charging the regenerative current, the regenerative current, which is a secondary energy, can be used as much as possible without wasting it. The fuel of the battery 11 can be saved. And since it is not necessary to enlarge the capacity | capacitance of the battery 12 more than necessary, the weight and magnitude | size of the vehicle which accommodates the battery 12 can be reduced, and cost can be made low.
[0146]
Further, an appropriate current is supplied from the fuel cell 11 without any special control. Therefore, even when the required current exceeds the maximum supply current value of the fuel cell 11, since a shortage of current is supplied from the battery 12, the vehicle travel is not hindered.
[0147]
Further, even when the actual measured value of the SOC of the battery 12 does not fall within the range of the reference value, the distribution of the current output from the fuel cell 11 and the battery 12 can be appropriately controlled. The battery 12 will not rise.
[0148]
Next, a main flowchart of the control operation of the fuel cell device will be described.
Step S1: The vehicle speed is detected.
Step S2 The change in the vehicle speed is stored.
Step S3: Torque to be generated by the motor 14 is detected.
Step S4: The value of the current supplied from the battery 12 is detected.
Step S5: Calculate the SOC of the battery 12.
Step S6: The value of the current supplied from the fuel cell 11 is detected.
Step S7: Determine the travel mode of the vehicle.
Step S8: The reference value of the SOC of the battery 12 is set according to the driving mode of the vehicle.
Step S9: It is determined whether or not the detected SOC of the battery 12 is within the range of the reference value. If it is within the range, the process proceeds to step S11. If it is not within the range, the process proceeds to step S10.
Step S10: Perform processing outside the SOC reference range.
Step S11: The accelerator opening θ is detected.
Step S12 The outputs of the fuel cell 11 and the battery 12 are controlled according to FIGS. 9 (a) to 9 (d).
[0149]
Next, a flowchart of a subroutine for processing outside the SOC reference range in step S10 will be described.
Step S10-1: It is determined whether the detected SOC of the battery 12 is equal to or lower than the lower limit of the reference value range. In the following cases, the process proceeds to step S10-2, and in the other cases, that is, when the upper limit of the reference value range is exceeded, the process proceeds to step S10-7.
Step S10-2: Set the current value of the charging current.
Step S10-3: It is determined whether the sum of the charging current and the required current is less than the maximum supply current value of the fuel cell 11. If it is less, the process proceeds to Step S10-4. If it is not less, the process proceeds to Step S10-19.
Step S10-4 A part of the current supplied from the fuel cell 11 is used for charging the battery 12.
Step S10-5: The IGBT 15a of the battery charge control circuit 15 is turned on.
Step S10-6: The fuel cell 11 is not controlled at all, and supplies the total current of the charging current and the required current, and the process is terminated.
Step S10-7: It is determined whether the required current is less than the maximum supply current value of the battery 12. If it is less, the process proceeds to step S10-8. If it is not less, the process proceeds to step S10-11.
Step S10-8: Current is supplied from the battery 12, and no current is supplied from the fuel cell 11.
Step S10-9: The IGBT 16a of the battery discharge control circuit 16 is turned on / off by a switching signal having a predetermined cycle, and the output voltage of the battery 12 is boosted.
Step S10-10 The fuel cell 11 is not controlled at all, and the process ends without supplying current.
Step S10-11: The current value of the current supplied from the battery 12 is set.
Step S10-12 In addition to the current from the battery 12, the current from the fuel cell 11 is also supplied to the motor 14.
Step S10-13: The current value of the current supplied from the battery 12 to the motor 14 is calculated.
Step S10-14 The IGBT 16a of the battery discharge control circuit 16 is turned on / off by a switching signal having a predetermined cycle, and the output voltage of the battery 12 is boosted.
Step S10-15 The fuel cell 11 is not controlled at all, and supplies a current having a value obtained by subtracting the current from the battery 12 from the required current, and the process is terminated.
Step S10-16: It is determined whether the required current is less than the maximum supply current value of the fuel cell 11. If it is less, the process proceeds to step S10-17, and if not, the process proceeds to step S10-20.
Step S10-17 Stop charging the battery 12.
Step S10-18 The IGBT 15a of the battery charge control circuit 15 is turned off.
Step S10-19 The fuel cell 11 is not controlled at all, and the requested current is supplied to end the process.
Step S10-20 Stop charging the battery 12.
Step S10-21 In addition to the current from the fuel cell 11, the current from the battery 12 is also supplied to the motor.
Step S10-22: Calculate the current value that the battery 12 supplies to the motor 14.
Step S10-23: The IGBT 16a of the battery discharge control circuit 16 is turned on / off by a switching signal of a predetermined period, and the output voltage of the battery 12 is boosted.
Step S10-24 The fuel cell 11 is not controlled at all, and the requested current is supplied to end the process.
[0150]
In addition, this invention is not limited to the said embodiment, It can change variously based on the meaning of this invention, and does not exclude them from the scope of the present invention.
[0151]
【The invention's effect】
As described above in detail, according to the present invention, in the fuel cell device, the load and the fuel cell are directly connected, and the power storage means circuit including the power storage means is connected in parallel with the fuel cell, and the power storage The means supplies the current to the load when the current supplied by the fuel cell is smaller than the current required by the load, and is charged by the regenerative power generated at the load and the current output by the fuel cell. The
[0152]
In this case, even if the required current required by the load exceeds the maximum supply current value of the fuel cell, a shortage of current is supplied from the power storage means. Further, since the power storage means is appropriately charged by the regenerative current or the like, the power storage means does not rise.
[0153]
In another fuel cell device, a fuel cell device comprising: a fuel cell; a load connected to an output terminal of the fuel cell; and a storage means circuit connected in parallel to the fuel cell with respect to the load. The power storage means circuit includes a power storage means, a booster circuit that boosts an output voltage of the power storage means and supplies a current to the load, and supplies a current output from the fuel cell to the power storage means. A charging circuit for charging the vehicle and a running state detecting means for detecting the running state of the vehicle, and the booster circuit and the charging circuit are selected according to the running state of the vehicle detected by the running state detecting means. Operate automatically.
[0154]
In this case, since the SOC of the power storage means can be appropriately controlled while having a simple circuit configuration, the regenerative current can be used as much as possible without wasting, and the fuel cell fuel can be saved. Can do. Moreover, it is not necessary to increase the capacity of the power storage means more than necessary. Further, a current corresponding to the required current is appropriately supplied from the fuel cell and the power storage means. Furthermore, since the power storage means is appropriately charged by the regenerative current or the like, the power storage means does not rise.
[0155]
In another fuel cell device, a fuel cell connected to a load, a storage means circuit connected in parallel to the fuel cell and the load, and a current from the storage means circuit is not supplied to the fuel cell In the fuel cell device including the diode elements arranged as described above, the power storage circuit includes a charging switching element and a boosting switching element connected in series with each other, and a reactor for the boosting switching element. Via a power storage means connected in parallel with each other, and a running state detecting means for detecting the running state of the vehicle, and according to the running state of the vehicle detected by the detecting means, the booster circuit and the charging circuit, Is activated selectively.
[0156]
In this case, since the SOC of the power storage means can be appropriately controlled while having a simple circuit configuration, the regenerative current can be used as much as possible without wasting, and the fuel cell fuel can be saved. Can do. In addition, since the output voltage of the power storage means can be appropriately boosted, a current corresponding to the required current is appropriately supplied from the power storage means. Furthermore, since the power storage means is appropriately charged by the regenerative current or the like, the power storage means does not rise.
[0157]
In still another fuel cell device, the load is a drive control device for a drive motor that drives the vehicle.
[0158]
In this case, although the circuit configuration is simple, the current corresponding to the required current is appropriately supplied from the fuel cell and the power storage means, so that the vehicle travel is not hindered.
[0159]
In still another fuel cell device, the booster circuit and the charging circuit are further controlled so that the SOC of the power storage means falls within a predetermined reference value range.
[0160]
In this case, since the distribution of the current output from the fuel cell and the power storage means can be appropriately controlled, there is no hindrance to the running of the vehicle, and the power storage means does not rise.
[0161]
In still another fuel cell device, the SOC reference value of the power storage means predicts the generation of a regenerative current according to the traveling state of the vehicle, and charges the power storage means with the regenerative current. Is set.
[0162]
In this case, since the SOC of the power storage means can be controlled more appropriately according to the driving mode of the vehicle, the regenerative current can be used as much as possible without wasting it at all, and the fuel cell fuel can be further saved. Can do.
[0163]
In still another fuel cell device, the power storage means is a circuit including a secondary battery and a capacitor.
[0164]
In this case, by appropriately controlling the distribution of the current output from the secondary battery and the capacitor and the distribution of the current charged in the secondary battery and the capacitor, the deterioration of the secondary battery and the capacitor can be prevented. In addition, the current required by the load can be output promptly and appropriately.
[0165]
In still another fuel cell device of the present invention, the power storage means is a capacitor.
[0166]
In this case, the current required by the load can be output quickly. Further, the weight of the power storage means and the occupied volume can be reduced.
[0167]
In still another fuel cell device of the present invention, the power storage means is a secondary battery.
[0168]
In this case, the storage capacity of the storage means can be easily increased.
[0169]
According to the present invention, in a control method for a fuel cell device, a fuel cell having both terminals connected to a load, a booster circuit, a charging circuit, and a power storage unit, and a power storage unit circuit connected in parallel to the fuel cell And controlling a current charged to the power storage means and a current supplied from the power storage means to the load.
[0170]
In this case, even if the required current requested by the load exceeds the maximum supply current value of the fuel cell, a shortage of current is supplied from the battery, so there is no hindrance to vehicle travel. . In addition, since the battery is appropriately charged, the battery will not rise.
[0171]
In another control method for the fuel cell device, the running state of the vehicle is further determined based on the latest past vehicle speed, accelerator opening θ, and the like.
[0172]
In this case, since the current travel mode is determined based on the latest past travel mode, the reliability is improved.
[0173]
In still another fuel cell device control method, the traveling state is further determined based on information from the vehicle position detection device.
[0174]
In this case, since the traveling state can be determined in real time, the determination reliability is extremely high.
[0175]
In still another fuel cell device control method, an SOC reference value of the electricity storage means is set in accordance with the determined running state, and the SOC of the electricity storage means falls within the reference value range. Thus, the current charged to the power storage means and the current supplied from the power storage means to the load are controlled.
[0176]
In this case, since the SOC of the power storage means can be controlled appropriately, the regenerative current can be used as much as possible without wasting it, and the fuel in the fuel cell can be saved. Moreover, since it is not necessary to increase the capacity of the power storage means more than necessary, the weight and size of the vehicle housing the power storage means can be reduced, and the cost can be reduced.
In still another fuel cell device control method, the SOC reference value of the power storage means predicts the occurrence of a regenerative current according to the running state, and charges the power storage means with the regenerative current. It is set to be possible.
[0177]
In this case, since the SOC of the power storage means can be controlled more appropriately according to the driving mode of the vehicle, the regenerative current can be used as much as possible without wasting it at all. Can be saved.
[0178]
In still another fuel cell device control method, the power storage means is a circuit including a secondary battery and a capacitor.
[0179]
In this case, the secondary battery and the capacitor can be prevented from deteriorating by appropriately controlling the distribution of the current output from the secondary battery and the capacitor and the distribution of the current charged in the secondary battery and the capacitor. In addition, the current required by the load can be output promptly and appropriately.
[0180]
In still another fuel cell device control method of the present invention, the power storage means is a capacitor.
[0181]
In this case, the current required by the load can be output quickly. Further, the weight of the power storage means and the occupied volume can be reduced.
[0182]
In still another fuel cell device control method of the present invention, the power storage means is a secondary battery.
[0183]
In this case, the storage capacity of the storage means can be easily increased.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram of a fuel cell device according to an embodiment of the present invention.
FIG. 2 is a view showing a conventional fuel cell device.
FIG. 3 is a diagram showing characteristics of a fuel cell and a battery in a conventional fuel cell circuit.
FIG. 4 is a diagram showing an example in which a battery and an electric double layer capacitor are combined and used as power storage means.
FIG. 5 is a diagram showing characteristics of a fuel cell and a battery according to an embodiment of the present invention.
FIG. 6 is a diagram showing an example of the relationship between the operation of the fuel cell circuit 10 and the travel mode in the embodiment of the present invention.
FIG. 7 is a diagram showing a basic concept of a control method for a fuel cell circuit according to an embodiment of the present invention.
FIG. 8 is a diagram showing the SOC value of the battery in various travel modes according to the embodiment of the present invention.
FIG. 9 is a diagram showing output ranges of the fuel cell and the battery in various travel modes according to the embodiment of the present invention.
FIG. 10 is a flowchart showing a control operation of the fuel cell circuit according to the embodiment of the present invention.
FIG. 11 is a first flowchart showing the operation of SOC out-of-range processing in the embodiment of the present invention.
FIG. 12 is a second flowchart showing the operation of the SOC out-of-range process in the embodiment of the present invention.
FIG. 13 is a third flowchart showing the operation of the SOC out-of-range process in the embodiment of the present invention.
[Explanation of symbols]
11 Fuel cell
17 Reactor

Claims (6)

A fuel cell;
A load connected to the output terminal of the fuel cell;
In the fuel cell device comprising a storage means circuit connected in parallel to the fuel cell for the load,
The power storage means circuit includes:
Power storage means;
A booster circuit that boosts the output voltage of the power storage means and supplies current to the load;
A charging circuit for supplying the current output from the fuel cell to the power storage means to charge the power storage means;
A traveling mode detection means for detecting a running mode of the vehicle based on the vehicle speed and the accelerator opening,
The boosting circuit and the charging circuit so that the SOC of the power storage means falls within a reference value range corresponding to the driving mode according to the driving mode of the vehicle detected by the driving mode detecting means. Are selectively operated. A fuel cell device characterized in that A fuel cell connected to the load;
A storage means circuit connected in parallel to the load with the fuel cell,
In a fuel cell device comprising a diode element arranged so that current from the power storage means circuit is not supplied to the fuel cell,
The power storage means circuit includes:
A charging switching element and a boosting switching element connected in series with each other;
Power storage means connected in parallel via a reactor to the boosting switching element;
A traveling mode detection means for detecting a running mode of the vehicle based on the vehicle speed and the accelerator opening,
According to the running mode of the vehicle detected by the traveling mode detection means, wherein as the SOC of power storage means falls within the range of the reference value set corresponding to the running mode, the said charge switching element A fuel cell device characterized by selectively operating a boosting switching element. The fuel cell device according to claim 1, wherein the load is a drive control device of a drive motor that drives a vehicle. It said storage means is a fuel cell device according to any one of claims 1 to 3, which is a circuit including a secondary battery and a capacitor. The fuel cell device according to any one of claims 1 to 3 , wherein the power storage means is a capacitor. It said storage means is a fuel cell device according to any one of claims 1 to 3 which is a secondary battery.

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