JP2004179113A - Control device for fuel cell vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely protect a load and a capacitor mounted on a fuel cell vehicle when the vehicle is operated. <P>SOLUTION: A control device 20 controls a current/voltage controller 12 so that voltage (secondary side voltage) outputted from the current/voltage controller 12 becomes either lower value or less of load protection voltage and capacitor protection voltage to the specified load protection voltage set to an electrical apparatus to which electric power is supplied from a fuel cell 11 and and the capacitor 13, in other words, to an output controller 14, a running motor 15, a load 16, and an S/C controller 17, and the like, and the specified protection voltage set in order to prevent the overcharge of the capacitor 13 to voltage between terminals of the capacitor 13. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a control device for a fuel cell vehicle.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, for example, a polymer electrolyte membrane fuel cell has a configuration in which a plurality of cells are stacked on a cell formed by sandwiching a polymer electrolyte membrane between a fuel electrode (anode) and an oxygen electrode (cathode) from both sides. Hydrogen is supplied as fuel to the fuel electrode, air is supplied to the oxygen electrode as an oxidant, and hydrogen ions generated by a catalytic reaction at the fuel electrode pass through the solid polymer electrolyte membrane. The electrode moves to the oxygen electrode and generates an electrochemical reaction with oxygen at the oxygen electrode.
Conventionally, a fuel cell vehicle equipped with such a fuel cell as a driving power source has conventionally been provided with a capacitor such as an electric double layer capacitor or an electrolytic capacitor to store the power generation energy of the fuel cell and to connect the traveling motor with an electric motor. 2. Description of the Related Art There is known a fuel cell vehicle configured to transfer energy.
In such a fuel cell vehicle, the capacitor is connected in parallel to the fuel cell via an output controller that controls the output current and output voltage of the fuel cell, and performs an output control operation, for example, a chopper-type power conversion circuit. The chopping operation and the like of the output controller provided is controlled, for example, according to the state of the fuel cell vehicle, the fuel cell, and the capacitor.
[0003]
[Patent Document 1]
JP 2001-357865 A
[Problems to be solved by the invention]
By the way, in the fuel cell vehicle according to one example of the related art, a predetermined upper limit voltage that can be applied to a load including a traveling motor according to a withstand voltage of a smoothing capacitor included in the load, for example. (Load protection voltage) is set.
In addition, the capacitor must be protected from being charged above a predetermined voltage (capacitor protection voltage). Further, when the temperature of the capacitor is relatively high, the electrolyte filled in the capacitor tends to be denatured. For example, when the capacitor protection voltage is set to a fixed value, there is a problem that the capacitor cannot be protected at a high temperature.
For this reason, if the load protection voltage and the capacitor protection voltage are not set to appropriate values, the load and the capacitor may not be able to be surely protected. When the regenerative power of the driving motor is supplied, there is a possibility that the energy efficiency of the fuel cell vehicle may be reduced by causing the fuel cell to perform unnecessary power generation or causing the traveling motor to perform unnecessary regeneration. .
The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a control device for a fuel cell vehicle that can reliably protect a load and a capacitor provided in the fuel cell vehicle when the fuel cell vehicle operates. Aim.
[0005]
[Means for Solving the Problems]
In order to solve the above problems and achieve the object, a control device for a fuel cell vehicle according to the present invention according to claim 1 includes a traveling motor capable of driving the vehicle and an electrochemical reaction when a reaction gas is supplied. , A capacitor charged by the generated power of the fuel cell and the regenerative power of the traveling motor, and output control means for controlling the output current and output voltage of the fuel cell (for example, in the embodiment) A current / voltage controller 12), and a load (for example, the electric device in the embodiment, that is, the output controller 14, the traveling motor 15, and the load including the traveling motor). Load protection voltage setting means (for example, step S02 in the embodiment) for setting a predetermined load protection voltage for the load 16 and the S / C output controller 17); Capacitor temperature detecting means (for example, the capacitor temperature sensor 24 in the embodiment) for detecting the temperature of the capacitor, and a capacitor protection voltage setting means for setting a capacitor protection voltage with respect to a voltage between terminals of the capacitor according to the temperature of the capacitor (For example, step S03 in the embodiment), wherein the output control unit sets the voltage output from the output control unit to be equal to or less than the smaller value of the load protection voltage or the capacitor protection voltage. It is characterized by:
[0006]
According to the control device for a fuel cell vehicle having the above configuration, even when the relative vertical relationship between the capacitor protection voltage and the load protection voltage changes in accordance with the temperature of the capacitor during operation of the fuel cell vehicle, the fuel cell By setting the output voltage at a value equal to or smaller than the smaller one of the capacitor protection voltage and the load protection voltage, the load and the capacitor provided in the fuel cell vehicle can be reliably protected.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a control device for a fuel cell vehicle according to an embodiment of the present invention will be described with reference to the accompanying drawings.
The control device 10 for a fuel cell vehicle according to the present embodiment includes a fuel cell 11, a current / voltage controller 12, a capacitor 13, an output controller 14, a traveling motor 15, as shown in FIG. , Load 16, S / C output controller 17, air compressor (S / C) 18, hydrogen tank 19a and hydrogen supply valve 19b, control device 20, fuel cell voltage sensor 21, output current sensor 22, a capacitor voltage sensor 23, a capacitor temperature sensor 24, an accelerator opening sensor 31, and an IG switch 32.
[0008]
The fuel cell 11 sandwiches a solid polymer electrolyte membrane composed of a cation exchange membrane or the like between a fuel electrode (anode) composed of an anode catalyst and a gas diffusion layer and an oxygen electrode (cathode) composed of a cathode catalyst and a gas diffusion layer. The fuel cell is formed by laminating a large number of fuel cells each having the above-mentioned electrolyte electrode structure sandwiched between a pair of separators.
A fuel gas (reaction gas) composed of hydrogen is supplied to the anode of the fuel cell 11 from a high-pressure hydrogen tank 19a via a hydrogen supply valve 19b, and hydrogen ionized by a catalytic reaction on the anode catalyst of the anode is appropriately cooled. Moves to the cathode through the humidified solid polymer electrolyte membrane, and electrons generated by this movement are taken out to an external circuit and used as DC electric energy. Air, which is, for example, an oxidizing gas (reactive gas) containing oxygen, is supplied to the cathode by an air compressor (S / C) 18, where hydrogen ions, electrons, and oxygen react to produce water. .
[0009]
A generated current (output current) taken out of the fuel cell 11 is input to a current / voltage controller 12, which includes a plurality of capacitor cells such as an electric double layer capacitor and an electrolytic capacitor. Are connected in series with each other.
The fuel cell 11, the current / voltage controller 12, and the capacitor 13 are connected to a traveling motor 15 via an output controller 14, for example, a cooling device (not shown) for the fuel cell 11 and the capacitor 13 and an air conditioner (not shown). ) Are connected in parallel to an air compressor (S / C) 18 via an S / C output controller 17.
[0010]
The current / voltage controller 12 includes, for example, a chopper-type power conversion circuit and the like. For example, the fuel is supplied by a chopping operation of the chopper-type power conversion circuit, that is, an on / off operation of a switching element included in the chopper-type power conversion circuit. The current value of the output current extracted from the battery 11 is controlled, and the chopping operation is controlled according to the duty of the control pulse input from the control device 20, that is, the on / off ratio.
For example, when the output current from the fuel cell 11 is prohibited, if the duty of the control pulse input from the control device 20 is set to 0%, the switching element included in the chopper type power conversion circuit is turned off. And the fuel cell 11 and the capacitor 13 are electrically disconnected. On the other hand, when the duty of the control pulse is set to 100% and the switching element is fixed in the ON state, the fuel cell 11 and the capacitor 13 are directly connected, so to speak, so that the output voltage of the fuel cell 11 and the voltage between the terminals of the capacitor 13 are reduced. Are equivalent values.
When the duty of the control pulse is set to an appropriate value between 0% and 100%, the current / voltage controller 12 changes the output current of the fuel cell 11, which is the primary current, to the duty of the control pulse. The current is limited as appropriate, and the obtained current is output as the secondary current.
[0011]
The output controller 14 includes, for example, a PWM inverter based on pulse width modulation (PWM), and controls the driving and the regenerative operation of the traveling motor 15 according to a control command output from the control device 20. For example, when driving the traveling motor 15, the DC power output from the current / voltage controller 12 and the capacitor 13 is converted into three-phase AC power based on the torque command input from the Supply. On the other hand, at the time of regeneration of the traveling motor 15, the three-phase AC power output from the traveling motor 15 is converted into DC power and supplied to the capacitor 13 to charge the capacitor 13.
The traveling motor 15 is, for example, a permanent magnet type three-phase AC synchronous motor using a permanent magnet as a field, and is driven and controlled by three-phase AC power supplied from the output controller 14. When the driving force is transmitted from the driving wheel side to the traveling motor 15 during the deceleration of the vehicle, the traveling motor 15 functions as a generator, generates a so-called regenerative braking force, and converts the kinetic energy of the vehicle body into electric energy. To be collected.
[0012]
The air compressor 18 takes in air from the outside of the vehicle, compresses the air, and supplies the compressed air to the cathode of the fuel cell 11 as a reaction gas.
The number of revolutions of a motor (not shown) for driving the air compressor 18 is controlled by an S / C output controller 17 having a PWM inverter by, for example, pulse width modulation (PWM) based on a control command input from a control device 20. Is controlled.
[0013]
For example, the control device 20 controls the operating state of the vehicle, the concentration of hydrogen contained in the reaction gas supplied to the anode of the fuel cell 11, the concentration of hydrogen contained in the exhaust gas discharged from the anode of the fuel cell 11, and the like. A command for the flow rate of the reactant gas supplied from the air compressor 18 to the fuel cell 11 based on the power generation state of the fuel cell 11, for example, a voltage between terminals of each of the plurality of fuel cells, an output current extracted from the fuel cell 11, and the like. A value and a command value for the valve opening of the hydrogen supply valve 19b are output, and the power generation state of the fuel cell 11 is controlled.
Further, the control device 20 outputs a control pulse for controlling the power conversion operation of the current / voltage controller 12 based on a power generation command for the fuel cell 11, and controls the current value of the output current extracted from the fuel cell 11.
[0014]
In addition, the control device 20 controls the power conversion operation of the PWM inverter provided in the output controller 14, and for example, when the driving motor 15 is driven, the control device 20 relates to the amount of depression of the accelerator pedal by the driver. A torque command is calculated based on the accelerator opening signal. When the control device 20 inputs the torque command to the output controller 14, a pulse width modulation signal corresponding to the torque command is input to the PWM inverter, and each phase current for generating the requested torque is generated. It is output to each phase of the traveling motor 15.
The control device 20 further controls the traveling motor based on the state of the capacitor 13, for example, the temperature of the capacitor 13, the total voltage that is the sum of the capacitor cell voltages of the plurality of capacitor cells, that is, the detected value of the voltage between the terminals of the capacitor 13, and the like. 15 regenerative operations are controlled.
For this reason, the control device 20 includes, for example, a detection signal output from a fuel cell voltage sensor 21 that detects a terminal voltage (fuel cell voltage) of each of a plurality of fuel cells constituting the fuel cell 11, A detection signal output from an output current sensor (not shown) that detects a current value of an output current extracted from the fuel cell 11, a detection signal output from an output voltage sensor 22 that detects an output voltage of the fuel cell 11, A detection signal output from a capacitor voltage sensor 23 that detects a voltage between terminals of the capacitor 13, a detection signal output from a capacitor temperature sensor 24 that detects the temperature of the capacitor 13, and a detection output from an accelerator opening sensor 31 A signal and a signal output from the IG switch 32 for instructing start of operation of the vehicle are input.
[0015]
Further, as will be described later, control device 20 controls a voltage that can be applied to electric equipment to which power is supplied from fuel cell 11 and capacitor 13, that is, output controller 14, traveling motor 15, load 16, and S / C output. Overcharge of the capacitor 13 with respect to a predetermined load protection voltage (for example, withstand voltage of a smoothing capacitor provided in the output controller 14 and the like) set for the controller 17 and the like, and a voltage between terminals of the capacitor 13 The voltage (secondary voltage) output from the current / voltage controller 12 is a smaller value of the load protection voltage or the capacitor protection voltage with respect to a predetermined capacitor protection voltage set to prevent the The current / voltage controller 12 is controlled as follows.
[0016]
The control device 10 for a fuel cell vehicle according to the present embodiment has the above-described configuration. Next, the operation of the control device 10 for a fuel cell vehicle, in particular, the operation for controlling the current / voltage controller 12 will be described with reference to the accompanying drawings. It will be described with reference to FIG.
[0017]
First, in step S01 shown in FIG. 2, a power generation command corresponding to, for example, an accelerator operation amount according to an accelerator operation amount of a driver is input to the S / C output controller 17 to supply a reaction gas to the fuel cell 11. At the same time, a torque command corresponding to the accelerator opening and the like is output to the output controller 14, and the driving motor 15 is driven by power supply from the fuel cell 11.
When the traveling motor 15 is driven, for example, the duty of the control pulse input to the current / voltage controller 12 is set to 100%, and the fuel cell 11 and the capacitor 13 are directly connected to each other. Thirteen terminals have the same value.
[0018]
Next, in step S02, the electric equipment to which electric power is supplied from the fuel cell 11 and the capacitor 13, that is, the output controller 14, the traveling motor 15, the load 16, the S / C output controller 17, and the like are set in advance. The obtained predetermined load protection voltage (for example, the load protection voltage VAC shown in FIG. 3) is obtained.
Next, in step S03, a predetermined table indicating the relationship between the capacitor protection voltage set for preventing the capacitor 13 from being overcharged and the temperature of the capacitor 13 with respect to the voltage between the terminals of the capacitor 13, for example, FIG. As shown in (1), a capacitor protection voltage corresponding to the temperature of the capacitor 13 detected by the capacitor temperature sensor 24 is calculated based on a table of the capacitor protection voltage VCAP, which changes in a tendency to decrease as the temperature TCAP of the capacitor 13 increases.
[0019]
Next, in step S04, it is determined whether the voltage output from the current / voltage controller 12 has exceeded the smaller value of the load protection voltage or the capacitor protection voltage.
If the result of this determination is “NO”, a series of processing ends.
On the other hand, if the result of this determination is “YES”, the flow proceeds to step S05.
Note that when the fuel cell 11 and the capacitor 13 are directly connected by the current / voltage controller 12 at the time of driving the traveling motor 15 or the like, the voltage output from the current / voltage controller 12 When the output current of the fuel cell 11 is equal to the output voltage of the battery 11 and the voltage between the terminals of the capacitor 13 and the output current of the fuel cell 11 is appropriately limited by the current / voltage controller 12, the output is output from the current / voltage controller 12. The voltage (secondary voltage) is equal to the voltage between the terminals of the capacitor 13.
[0020]
In step S05, the voltage (secondary voltage) output from the current / voltage controller 12 is set to be smaller than the smaller value of the load protection voltage or the capacitor protection voltage (for example, the area shown in FIG. 3). A), the duty of the control pulse input to the current / voltage controller 12 is set to an appropriate value between 0% and 100%, and the primary side is set according to the duty of the control pulse. The output current of the fuel cell 11, which is a current, is appropriately limited, the limited current is output to the capacitor 13 side as a secondary current, and a series of processing ends.
[0021]
As described above, according to the control device 10 for a fuel cell vehicle according to the present embodiment, as shown in FIG. 3, for example, the relative vertical relationship between the capacitor protection voltage and the load protection voltage when the fuel cell vehicle operates is determined. Even when the temperature changes according to the temperature of capacitor 13, electric equipment to which power is supplied from fuel cell 11 and capacitor 13, that is, output controller 14, traveling motor 15, load 16, and S / C output controller 17 and the capacitor 13 can be reliably protected.
[0022]
In the above-described embodiment, when driving the traveling motor 15, the voltage (secondary voltage) output from the current / voltage controller 12 is the smaller of the load protection voltage or the capacitor protection voltage. Although the output current of the fuel cell 11 is limited by the current / voltage controller 12 so as to be equal to or less than the value of In the embodiment, the power conversion operation of the output controller 14 is controlled so that the secondary voltage of the current / voltage controller 12 is equal to or less than the smaller value of the load protection voltage or the capacitor protection voltage.
Thereby, it is possible to reliably prevent the capacitor 13 from being charged from the fuel cell 11 and the traveling motor 15 so as to exceed the capacitor protection voltage.
[0023]
【The invention's effect】
As described above, according to the fuel cell vehicle control device of the present invention, when the fuel cell vehicle operates, the relative vertical relationship between the capacitor protection voltage and the load protection voltage depends on the temperature of the capacitor. Even if it changes in response, the load and capacitor provided in the fuel cell vehicle can be reliably protected.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a control device for a fuel cell vehicle according to an embodiment of the present invention.
FIG. 2 is a flowchart showing the operation of the control device for a fuel cell vehicle shown in FIG.
FIG. 3 is a graph showing an example of a relative vertical relationship between a capacitor protection voltage VCAP and a load protection voltage VAC, which change according to a capacitor temperature TCAP.
[Explanation of symbols]
10 Control device for fuel cell vehicle 12 Current / voltage controller (output control means)
13 Capacitor 14 Output controller (load)
15 Traveling motor (load)
16 Load 17 S / C output controller (load)
24 Capacitor temperature sensor (capacitor temperature detecting means)
Step S02 Load protection voltage setting means Step S03 Capacitor protection voltage setting means

Claims (1)

A traveling motor capable of driving a vehicle, a fuel cell that is supplied with a reactive gas to generate electricity by an electrochemical reaction, a capacitor that is charged by the power generated by the fuel cell and the regenerative power of the traveling motor, and the fuel cell Control device for controlling the output current and output voltage of the fuel cell vehicle, comprising:
Load protection voltage setting means for setting a predetermined load protection voltage for a load including the traveling motor,
Capacitor temperature detecting means for detecting the temperature of the capacitor;
Capacitor protection voltage setting means for setting a capacitor protection voltage for a voltage between terminals of the capacitor according to a temperature of the capacitor,
The control device for a fuel cell vehicle, wherein the output control means makes the voltage output from the output control means equal to or less than a smaller value of the load protection voltage or the capacitor protection voltage.

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