KR101519666B1 - Control method for fuel cell hybrid vehicle - Google Patents

Abstract

The present invention relates to a control method of a fuel cell hybrid vehicle, and it is an object of the present invention to provide a control method of a fuel cell hybrid vehicle, in which a supercap usage period is limited to a lower limit value of a fuel cell voltage or a lower limit value of a main bus voltage, In order to solve this problem, the supercap energy (voltage) is extended to a set lower limit value of the supercap voltage by using the bidirectional DC / DC converter of the supercap output stage in the supercap discharge mode to increase the power assist amount of the supercap, To a control method of a fuel cell hybrid vehicle.

Fuel cell, supercap, hybrid, direct connection mode, charge mode, discharge mode, mode switching, power assist

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a control method for a fuel cell hybrid vehicle,

The present invention relates to a fuel cell vehicle, and more particularly, to a control method of a fuel cell hybrid vehicle using a fuel cell as a main power source and a separate power storage means as an auxiliary power source.

A fuel cell system applied to a hydrogen fuel cell vehicle, which is one of environmentally friendly future vehicles, includes a fuel cell stack that generates electric energy from an electrochemical reaction of a reaction gas, a hydrogen supply device that supplies hydrogen as fuel to a fuel cell stack, An air supply device for supplying air containing oxygen, which is an oxidizing agent required for the electrochemical reaction, to the fuel cell stack, an operation of controlling the operation temperature of the fuel cell stack by discharging heat, which is a by- A heat and water management system that performs management functions, and a fuel cell system controller that controls overall operation of the fuel cell system.

In the fuel cell vehicle equipped with such a fuel cell system, when the fuel cell alone is used as the power source of the vehicle, the fuel cell takes charge of all the loads constituting the vehicle, so that the performance deterioration occurs in the fuel cell efficiency- . In addition, when a sudden load is applied to the vehicle, the output voltage of the fuel cell dips instantaneously and fails to supply sufficient power to the driving motor, thereby deteriorating the performance of the vehicle (since electricity is generated by a chemical reaction, . In addition, since the fuel cell has a unidirectional output characteristic, the energy drawn from the drive motor can not be recovered during the braking of the vehicle, thereby deteriorating the efficiency of the vehicle system.

In order to overcome the disadvantages described above, a fuel cell hybrid vehicle is being developed. The fuel cell hybrid vehicle is a separate auxiliary power source for supplying power required for driving a motor in addition to a fuel cell which is a main power source in a large vehicle such as a bus, as well as a small vehicle. A high voltage battery or a super capacitor ).

FIG. 1 is a power net diagram of a fuel cell-supercap direct hybrid system according to the related art. The power net configuration of a fuel cell-supercap hybrid vehicle includes a fuel cell (stack) 2 used as a main power source, A supercap precharge unit 9 interposed between the main bus terminal 3 serving as an output side of the fuel cell 2 and the supercap 10 and a drive motor 8 A motor controller (not shown) connected to the output side of the fuel cell 2 and the supercap 10 to generate a three-phase PWM (Pulse Width Modulation) by receiving a direct current from the fuel module 2 and controlling motor driving and regenerative braking A motor control unit (MCU) 7 (including an inverter). The super-cap initial charging unit 9 is used to charge the discharged super-cap voltage only at the initial start-up.

In this configuration, the fuel cell 2 as a main power source receives hydrogen from the hydrogen tank 1 and receives air by an air blower (not shown) to generate electricity by electrochemical reaction between hydrogen and oxygen in the air . The drive motor 8 and the MCU 7 are connected directly to the fuel cell 2 through the main bus terminal 3 and the supercap 10 is connected to the initial charge unit 9).

In addition, a low voltage DCDC converter (LDC) 11 for converting an output between a high voltage and a low voltage and a low voltage battery (12V auxiliary battery) 12 for driving an analog current component are connected to the main bus terminal 3 A load such as an air conditioner 13 and a heater (for cooling and heating) 14, which are directly supplied with high-voltage power via the main bus terminal 3, are connected.

(Fuel Cell BOP, air blower, hydrogen recirculation blower, water pump, etc.) 16 for driving the fuel cell 2 is connected to the main bus terminal 3 to facilitate starting of the fuel cell, The bus terminal 3 is provided with various relays 4 and 5 for facilitating power interruption and connection and a blocking diode 6 for preventing a reverse current from flowing through the fuel cell 2. Reference numeral 15 denotes a driver of the fuel cell flow 16, 17 is a heater for supplying heat to facilitate cold start of the fuel cell 2, 18 is a current consuming current of the fuel cell Lt; / RTI >

Conventional fuel cell-supercompact hybrid system that does not use power conversion devices such as DC / DC converter, DC / DC chopper and the like is a supercap by automatic power assist and regenerative braking by supercap due to the characteristics of direct- (Automatic regenerative braking function), and it has advantages of high control reliability, fuel cell durability increase, fuel economy excellent (regenerative braking big, supercap self efficiency). In particular, when the power is continuously outputted from the fuel cell, the supercap is charged with surplus power when the power is left, and when the power is insufficient, supplementary power (auxiliary output / power assist) Mode is being applied.

However, the conventional fuel cell-supercap hybrid system is disadvantageous in that the super-cap usage period is limited to the lower limit value of the fuel cell voltage or the lower limit value of the main bus voltage, so that the energy of the supercap can not be fully utilized.

As a prior art relating to a fuel cell-supercap hybrid system, the patent No. 862467 relates to a multifunctional resistance device and a control method thereof, and it relates to a multifunctional resistance device and a control method thereof, A method of performing multi-functions such as fuel cell voltage rise and fall control during braking control, start-up and shutdown, super-cap discharge control during maintenance of a supercap, preheating of a simultaneous fuel cell system in a cold state, and indoor heating.

As an example of the prior art of a fuel cell hybrid system using a power conversion device different from a fuel cell-supercap direct type structure, U.S. Patent 6484075 discloses a patent for an idle stop control of a fuel cell hybrid system (using a battery or a supercap) , A power converter (unidirectional DC / DC chopper) is installed at the output terminal of the fuel cell, and power cutoff and power supply resumption control of the fuel cell are performed through this device. The idle state is determined by the number of revolutions of the wheels, the operation of the brake, the battery state of charge (SOC), the electric load, etc., and then the power supply is cut off by the reaction gas shutoff of the fuel cell. A power conversion device is mounted for controlling the stoppage of fuel cell generation in the idle section such as resuming the power supply by the fuel cell.

U.S. Patent No. 6,920,948 is a patent on power distribution control (fuel cell output and battery output ratio) of a fuel cell-battery hybrid system. A bidirectional DC / DC converter is mounted at the battery output terminal to control the charge / . In this hybrid system, there is no operation mode in which the fuel cell and the battery are directly connected, and all the output of the battery goes through DC / DC.

However, the above-mentioned patent also does not disclose a method for increasing the amount of power assist when rushing or overtaking acceleration in performing power assist using supercap energy, and an optimal control method for starting, traveling, and shutdown.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above circumstances, and it is an object of the present invention to solve the problem that energy of a supercap can not be fully utilized in a fuel cell-supercap hybrid vehicle, increase the power assist amount of a supercap, And to provide a control method of a fuel cell hybrid vehicle capable of improving overtaking performance.

To achieve the above object, the present invention provides a fuel cell system comprising: comparing a super-cap voltage with a fuel cell voltage lower limit during running of a fuel cell-super-cab hybrid vehicle; Switching to a super-cap discharge mode in which a direct connection between the fuel cell and the super-cap is released when the super-cap voltage is equal to or lower than the lower limit of the fuel cell voltage, and a super-cap discharge and an output assistance are performed through the bidirectional DC / And the supercap output assists the fuel cell output within a range in which the supercap voltage exceeds a predetermined lower limit value of the supercap voltage in the supercharging mode during driving of the vehicle.

Here, the supercap voltage lower limit value is set to be lower than the lower limit value of the fuel cell voltage.

The present invention also relates to a method of controlling a fuel cell-supercap hybrid vehicle, comprising the steps of: comparing a supercap voltage with a main bus voltage lower limit at the start of the fuel cell-supercap hybrid vehicle; And if the supercap voltage is lower than the lower limit of the main bus voltage, proceeding to start the fuel cell in a supercharged discharge mode in which supercharging is performed through the bidirectional DC / DC converter with the direct connection between the fuel cell and the supercap being canceled During the start-up of the fuel cell, in the super-cap discharge mode, the super-cap energy is used to start the fuel cell within a range in which the super-cap voltage exceeds a predetermined lower limit value of the super-cap voltage.

The present invention also relates to a method of controlling a fuel cell-supercap hybrid vehicle, comprising the steps of: comparing a supercap voltage during a shutdown of a fuel cell-supercap hybrid vehicle with a lower limit voltage of the main bus; And if the super-cap voltage is lower than the lower limit of the main-bus voltage, proceeding to fuel cell shutdown in a super-cap discharge mode in which supercharging is performed through the bidirectional DC / DC converter with the direct connection between the fuel cell and the super- During the fuel cell shutdown, in the super-cap discharge mode, the fuel cell shutdown proceeds using super-cap energy within a range in which the super-cap voltage exceeds a predetermined lower limit value of the super-cap voltage.

At this time, the set lower limit value of the supercap voltage is set to be lower than the lower limit value of the main bus voltage.

Accordingly, in the control method of the fuel cell hybrid vehicle according to the present invention, the supercap energy (voltage) is extended to the set lower limit of the supercap voltage by using the bidirectional DC / DC converter of the supercap output stage in the supercap discharge mode, The power assist amount of the percap can be increased, and the oscillation and overtaking performance of the vehicle can be improved.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains.

FIG. 2 is a power net configuration diagram of a fuel cell-supercap hybrid system according to the present invention.

As shown in the figure, a supercap 200, which is a power storage means used as an auxiliary power source, is connected in parallel with a fuel cell (fuel cell stack) 100 as a main power source. The supercap 200 includes a bidirectional DC / DC converter 210 to the main bus 101, which is the output side of the fuel cell 100. In this way, the two power sources, that is, the fuel cell 100 and the supercap 200 are connected in parallel to each load in the system via the main bus terminal 101.

An inverter 301 for rotating the driving motor 302 is connected to the output side of the fuel cell 100 and the supercap 200 through the main bus terminal 101 so that the control signal applied to the controller 500 The power supplied from the fuel cell 100 or the supercap 200 is phase-converted to drive the drive motor 302. [

The DC / DC converter 210 is disposed at an output terminal of the super cap 200 to DC / DC convert the power output from the fuel cell 100 to be supplied to the super cap 200 to be charged, DC / DC converter for supplying power to each load in the system such as the drive motor 302 and the fuel cell. During braking control, regenerative energy generated in the drive motor 302 is DC / DC converted and supplied to the super cap 200 to be charged.

A high voltage driving component 220 that is operated by receiving a high voltage power such as a Balance Of Plant (BOP), an air conditioner and a heater (for heating and cooling) necessary for driving a fuel cell as a system load is installed in the fuel cell 100 or the supercap 200 , And is connected to the main bus terminal 101 so as to be driven by the output of the low voltage battery 400. The fuel cell includes a hydrogen recirculation blower of a hydrogen supply device, an air blower of an air supply device, and a water pump for cooling water circulation.

A low voltage DC / DC converter (LV DC / DC converter) 410 is connected to the main bus 101 for switching the output between the high voltage and the low voltage. And a low voltage driving part 420 is connected to the low voltage battery 400.

A reverse voltage prevention diode 102 is provided at the output side of the fuel cell 100 to block the surge voltage from being supplied to the fuel cell 100. A reverse voltage prevention diode 102 is connected to the rear end of the reverse voltage prevention diode 102, (110). The load device 110 is a stack current consuming load installed on the output side of the fuel cell 100. In the fuel cell shutdown mode, the load device 110 is used for exhausting the cathode oxygen of the stack and for removing the voltage. And is operated by supplying the current of the fuel cell 100 selectively according to the operation of the relay 111 which is switched on / off by the signal.

Also, the fuel cell-supercap hybrid system of the present invention is installed between the fuel cell 100 and the supercap 200 for fuel cell-supercap direct mode operation different from the supercap charging mode and the discharging mode, And a direct connection relay 201 for selectively directing / disconnecting the supercap 200. The direct connection relay 201 is controlled on / off by a control signal applied from the controller 500, Mode and a different operation mode (super-cap charge mode and discharge mode).

The controller 500 (including the fuel cell system controller, the converter controller, the power distribution controller, etc.) includes a fuel cell system control, drive and output control of the bidirectional DC / DC converter 210, control of the low voltage DC / , Power distribution control, and other operations related to the operation of the fuel cell-supercap hybrid system.

In the present invention, the controller 500 basically controls the driving of each component in the system during all steps of starting, running, braking, and shutdown (start-off) A brake pedal signal (acceleration judgment), and a voltage detection signal in the system, that is, a signal indicative of the presence or absence of the brake pedal (on / off signal) A voltage detector 502 for detecting the voltage of the main bus 101 and a voltage detector 503 for detecting the voltage of the supercap 200 And controls the system drive based on the signal.

The operation control method according to the present invention in a vehicle mounted with the above-described fuel cell-supercap hybrid system will now be described.

In order to solve the disadvantage that the super-cap usage period is limited to the lower limit value of the fuel cell voltage or the lower limit value of the main bus voltage in the conventional fuel cell-supercap hybrid vehicle, the energy of the supercap can not be utilized sufficiently. In the present invention, (Voltage) of the supercap 200 is increased by using the bidirectional DC / DC converter 210 of the output stage of the DC / DC converter 210 to extend the supercap energy (voltage) to the set lower limit of the supercap voltage Increase), and improve the oscillation and overtaking performance of the vehicle.

In the present invention, the controller 500 drives the direct-connection switch 201 and the bidirectional DC-DC converter 210 during the entire start-up (including cold start) of the vehicle and all the processes of running, braking, and shutdown (including cold shutdown) Supercomputer direct mode (direct connection relay on), supercap charging mode (direct connection relay off), supercap discharge mode (direct connection relay mode) in which the fuel cell 100 and the supercap 200 are directly connected by the direct coupling relay 201 Off), and the mode transition and supercap control are performed during the oscillation / overtaking, regenerative braking, normal start / normal shutdown, cold start / cold shutdown using these three operation modes.

The fuel cell-supercap direct mode is a mode in which the fuel cell 100 and the super-cap 200 are directly connected to each other (direct-coupled relay-on) 200 are automatically charged and discharged.

The supercap charging mode is executed when the supercap charging is completed and the supercap discharged after the supercap discharge is charged (supercap charging of low / middle output), the supercap discharge mode is the startup / shutdown (including cold / cold shutdown) Is executed to increase the power assist.

3A to 3C are diagrams showing power flow in each operation mode according to the present invention, wherein FIG. 3A shows a fuel cell-supercap direct coupling mode, FIG. 3B shows a supercap charging mode, and FIG. 3C shows a supercap discharge mode . 4 is a diagram illustrating the characteristics of each operation mode according to the present invention.

As shown in the figure, in the fuel cell-supercap direct connection mode, charging / discharging of the supercap is automatically performed according to the voltage state of the fuel cell 100, the supercap 200, and the main bus terminal 101 during normal traveling, ) From the fuel cell 100 or the drive motor 302 (at the time of regenerative braking) at the time of charging to the main bus terminal 101 (at the time of regenerative braking) while the fuel cell 100 and the main bus terminal 101 are directly connected to the super- And the power flow from the supercap 200 to the main bus terminal 101 at the time of discharging.

In the super-cap charging mode, the main bus 101 and the DC / DC converter 210 are connected to the fuel cell 100 via the main bus 101 and the DC / DC converter 210 for the initial charging of the super- The power flow to the supercap 200 is displayed.

In the super-cap discharge mode, power flow from the super-cap 200 to the main bus terminal 101 via the DC / DC converter 210 is shown for the purpose of increasing the power assist.

FIG. 5 is a diagram showing the operation mode control state in which the power assist of the supercap is increased in the acceleration / overtaking acceleration, as compared with the prior art. As shown in FIG. 5, the fuel cell output in the fuel cell- However, in the present invention, when the super-cap voltage is within the lower limit of the set super-cap voltage (lower limit value), the DC / DC converter is switched to the low- A supercap discharge mode is performed in which the fuel cell output is assisted. The lower limit value of the supercap voltage is set to be lower than the lower limit value of the fuel cell voltage, so that the use period of the supercap energy can be extended. As described above, in the present invention, the supercap energy can be used up to the lower limit value of the supercool voltage by using the discharge mode of the bidirectional DC / DC, whereas the supercap energy (voltage) Accordingly, the power assist amount of the supercap increases, and the oscillation and overtaking performance of the vehicle can be improved.

6 is a diagram illustrating an operation mode control state for explaining the energy assist increase of the cold snap super cap in the present invention. In the related art, supercap energy (voltage) However, in the present invention, it is possible to use up to the lower limit value of the supercap voltage set in the supercap discharge mode. At this time, the lower limit value of the supercap voltage is set to be lower than the lower limit voltage of the main bus voltage, so that the supercap energy assistance is increased as the use period of the supercap energy is expanded, so that the number of times of cold starting can be increased while minimizing the use of the 12- have. After completion of the cold start in the super-cap discharge mode, the super-cap charging mode is switched to the super-cap charging mode so that the vehicle can be switched to the fuel cell-supercap direct-connection mode.

The capacity of the existing heat sink can be minimized since the heat sink function for the self-heating process of the fuel cell can be performed through the supercap charging. The self-heating of the fuel cell is an essential process for raising the temperature inside the stack through powering of the fuel cell after completion of the cold start. In the case of A> B in FIG. 6, a separate heat sink (load for exhausting AB difference, ) Is required. In the present invention, the supercap energy exhausted through the supercap charging mode is charged, and the supercap charging performs the function of the heat sink for the heat generation of the fuel cell itself.

7 and 8 are flowcharts showing an example of mode switching according to the present invention. FIG. 7 shows an example of mode switching during startup and running. FIG. 8 shows an example of mode switching .

7, when the controller 500 detects a key on from the key signal, it determines whether the super-cap voltage exceeds the main bus voltage based on the detection signal of the voltage detector 503 (S11) When the supercap voltage exceeds the main bus terminal voltage, the direct switch 201 is turned on by the control signal applied from the controller 500 and is controlled to the fuel cell-supercap direct connection mode (M1 mode) (S12).

At this time, by using the output energy of the supercap 200, various loads such as an air blower, a hydrogen recirculation blower, and the like including a fuel cell type are required to start the fuel cell (including cold start) Power supply) The fuel cell start is completed (S13, S14).

On the other hand, if the super-cap voltage is below the lower limit of the main bus voltage, the startup is completed in the super-cap discharge mode (M3 mode) using the output energy of the super-cap 200 within the set lower limit of the super-cap voltage (S15 to S18). That is, by using the energy output from the supercap 200 through the output control of the DC / DC converter 210 under the condition that the supercap voltage is within the lower limit (exceeding the lower limit), the fuel cell including the fuel cell type (Including power supply to the starter for starting) and start the engine.

If the super-cap voltage is below the set super-cap voltage lower limit, the super-cap discharge mode is stopped (S19) and the voltage of the low-voltage battery 400 is boosted through boost control of the low-voltage DC / DC converter 410, (Including start-up), the start-up is completed (S20, S21).

After the startup is completed, the mode is switched to the super-cap charging mode (M2 mode) to perform the initial charging of the super-cap (S22), and then it is determined whether the super-cap voltage has risen to reach a certain level with respect to the fuel cell voltage (S23) When the voltage rises to the target value, the fuel cell is switched to the supercap direct mode (M1 mode) (direct switch on) (S24) and the supercap automatic charge / discharge is performed in a state where the fuel cell 100 and the supercap 200 are directly connected (S25) and the vehicle is driven.

During super-cap automatic charging and discharging, the super-cap output basically assists the fuel cell output during the super-cap discharging. When the super-cap voltage becomes lower than the fuel cell voltage lower limit in the fuel cell-supercap direct coupling mode (M1 mode) , The direct connection relay 201 is turned off and the supercharging discharge mode is switched to the M3 mode (S27).

In the supercap discharge mode, the supercap output is made through the DC / DC converter 210 until the supercap voltage drops due to the discharge and reaches the lower limit value of the supercap voltage. Thus, until the supercap voltage reaches the lower limit value, An auxiliary vehicle travel is performed (S28).

When the controller 500 detects a regenerative braking condition by referring to a brake signal or the like while the vehicle is running or determines that the super-cap voltage is lower than the super-cap voltage lower limit value in the super-cap discharge mode, the super- S31) The supercap 200 is charged with the energy generated by the fuel cell 100 or the regenerative energy generated by the driving motor 302 (S32).

Next, referring to FIG. 8, the operation mode control at the time of fuel cell shutdown (including the cold shutdown) will be described. When the controller 500 detects a key off by a key signal input, (S41). When the voltage exceeds the lower limit value of the main bus voltage, normal shutdown is performed using supercap energy in the fuel cell-supercap direct coupling mode (direct coupling relay ON) (M1 mode) (S42 to S44 ).

For example, the air supply is interrupted while the hydrogen supply is maintained, and the relay 111 is turned on to consume the current output from the fuel cell 100 in the load device 110, Exhaustion and voltage are removed. At this time, the electric energy required for the shutdown process such as the hydrogen recirculation blower uses the supercap energy.

On the other hand, if the super-cap voltage is less than the lower limit of the main bus voltage after the start-up detection, the direct-connect relay 201 is turned off and the normal shutdown process is performed using the supercap energy in the supercharged discharge mode (M3 mode) (S45 to S48) . At this time, supercap output control is performed through the DC / DC converter 200, and the shutdown by the supercap discharge mode proceeds within a range in which the supercap voltage exceeds the supercap voltage lower limit of the supercap discharge mode.

If the super-cap voltage is below the super-cap voltage lower limit, the supercap discharge mode (M3 mode) is stopped (S49) and the voltage of the low-voltage battery 400 is boosted through the boost control of the low- Is used as electric energy required in the shutdown process (S50, S51).

As described above, according to the present invention, when starting or shutting down, the startup or shutdown process is performed using the supercap energy within the lower limit value of the fuel cell voltage or the lower limit value of the main bus voltage, which is not lower than the lower limit value of the main bus voltage, thereby reducing the frequency of use of the 12V low voltage battery.

Particularly, when the vehicle starts up and accelerates and accelerates, the supercap usage period is extended to the lower limit value of the supercap voltage, thereby increasing the amount of supercap power assist and improving the oscillation and overtaking performance of the vehicle.

FIG. 9 is a diagram illustrating an overall operation mode switching state of the fuel cell-supercap hybrid vehicle according to the present invention. In FIG. 9, a supercap charging mode (M2 mode) ), A supercap discharge mode (M3 mode) in which the supercap performs the power assist until the supercap voltage reaches the set lower limit of the supercap voltage, a supercap charging mode in the regenerative braking mode, and a fuel cell- As shown in Fig.

In the fuel cell-supercap serial mode (M1 mode), the system is switched to the supercap discharge mode (M3 mode) during the cold start process after the shutdown to complete the cold start. (M3 mode) during a shutdown (cold shutdown) process at a temperature lower than a freezing point after the vehicle travels in a fuel cell-supercap direct mode (M1 mode) ). ≪ / RTI >

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. And are also included in the scope of the present invention.

1 is a power net configuration diagram of a fuel cell-supercap direct-coupled hybrid system.

2 is a power net configuration diagram of a fuel cell-supercap hybrid system according to the present invention.

FIGS. 3A to 3C are diagrams showing power flows in an operation mode according to the present invention, wherein FIG. 3A shows a fuel cell-supercap direct mode, FIG. 3B shows a supercap charging mode, and FIG. 3C shows a supercap discharge mode.

4 is a diagram showing the characteristics of each operation mode according to the present invention.

FIG. 5 is a view showing the operation mode control state of the present invention in which the power assist of the supercap is increased in the case of the acceleration of the oscillation / overtaking, compared with the conventional case.

Fig. 6 is an exemplary view showing an operation mode control state for explaining the energy-assisted increase of the instantaneous super-cap in the present invention. Fig.

FIGS. 7 and 8 are flowcharts showing an example in which mode switching according to the present invention is performed. FIG. 7 shows an example of mode switching during startup and running, and FIG. .

9 is a diagram illustrating a general operation mode switching state of the fuel cell-supercap hybrid vehicle according to the present invention.

Description of the Related Art

100: Fuel cell 200: Supercap

210: bidirectional DC / DC converter 220: high voltage driven component

301: inverter 302: drive motor

400: Low Voltage Battery 410: Low Voltage DC / DC Converter

Claims (8)

Comparing the supercap voltage with the fuel cell voltage lower limit during running of the fuel cell-supercap hybrid vehicle; Switching to a super-cap discharge mode in which direct connection between the fuel cell and the super-cap is canceled when the super-cap voltage is below the lower limit of the fuel cell voltage, and super-cap discharge and output assistance is performed through the bidirectional DC / DC converter at the super- Lt; / RTI > The supercap output assists the fuel cell output within a range in which the supercap voltage exceeds a predetermined lower limit of the supercap voltage in the supercharging mode during driving of the vehicle, Comparing the supercap voltage with the main bus voltage lower limit at startup of the fuel cell-supercap hybrid vehicle; If the super-cap voltage is lower than the lower limit of the main-bus voltage, proceeding to start the fuel cell in a super-cap discharge mode in which the super-cap discharge is performed through the bidirectional DC / DC converter with the direct connection between the fuel cell and the super- Further comprising: Wherein the fuel cell start-up is performed using supercap energy within a range in which the super-cap voltage exceeds a predetermined lower limit value of the super-cap voltage in the super-cap discharge mode during starting the fuel cell. The method according to claim 1, Wherein when the supercap voltage is lower than the set supercap voltage lower limit value or the regenerative braking condition is detected in the supercap discharge mode, the supercap charging mode is switched to the supercap charging mode in which the supercap charging is performed through the bidirectional DC / DC converter Control method. The method according to claim 1 or 2, Wherein the supercap voltage lower limit value is set to be lower than the lower limit value of the fuel cell voltage. delete The method according to claim 1, Wherein when the super-cap voltage is lower than the predetermined super-cap voltage lower limit in the super-cap discharge mode, the super-cap discharge is stopped and the low-voltage DC / DC converter is boosted to start the fuel cell using energy of the low-voltage battery. A method of controlling a vehicle. The method according to claim 1, Comparing the supercap voltage with the main bus voltage lower limit during shutdown of the fuel cell-supercap hybrid vehicle; Performing fuel cell shutdown in a super-cap discharge mode in which a super-cap discharge is performed through the bidirectional DC / DC converter in a state where the direct connection between the fuel cell and the super-cap is released if the super-cap voltage is lower than a lower limit value of the main bus voltage; Further comprising: Wherein the fuel cell shutdown is performed using super-cap energy within a range in which the super-cap voltage exceeds a predetermined lower limit value of the super-cap voltage in the super-cap discharge mode during shutdown of the fuel cell. The method of claim 6, Wherein when the supercap voltage is lower than the set supercap voltage lower limit value in the supercap discharge mode, the supercap discharge is stopped and the low voltage DC / DC converter is boosted controlled so that the fuel cell shutdown proceeds using energy of the low voltage battery. A method of controlling a vehicle. The method according to any one of claims 1 to 7, Wherein the set lower limit value of the supercap voltage is set to be lower than the lower limit value of the main bus voltage.

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