FUEL CELL SYSTEM AND FUEL SUPPLYING CONTROL METHOD THEREOF

1 . A fuel cell system, comprising:

a three-way valve installed on a hydrogen supply line between a fuel cell stack and a hydrogen tank;

a first hydrogen supply valve installed on a first hydrogen supply line branching off by the three-way valve and configured to variably adjust a hydrogen supply pressure;

a second hydrogen supply valve installed on a second hydrogen supply line branching off by the three-way valve and configured to adjust the hydrogen supply pressure to a constant pressure; and

a controller configured to control a supply of hydrogen to one of the first hydrogen supply line and the second hydrogen supply line according to a state of the hydrogen tank while the fuel cell stack operates.

2 . The fuel cell system of claim 1 , wherein the three-way valve includes:

a first port through which the supply of hydrogen being supplied from the hydrogen tank is introduced;

a second port configured to variably adjust a pressure of the hydrogen introduced through the first port and discharge the pressure-adjusted hydrogen through the first hydrogen supply line; and

a third port configured to adjust the pressure of the hydrogen introduced through the first port and discharge the pressure-adjusted hydrogen through the second hydrogen supply line.

3 . The fuel cell system of claim 2 , wherein the controller controls opening or closing of one or more of the first port, the second port, and the third port by determining whether an internal pressure and a state of fuel (SoF) of the hydrogen tank satisfy a reference pressure condition.

4 . The fuel cell system of claim 3 , wherein, when the internal pressure of the hydrogen tank exceeds a reference pressure or the SoF of the hydrogen tank exceeds a reference value, the controller determines that the reference pressure condition is satisfied.

5 . The fuel cell system of claim 4 , wherein, when the state of the hydrogen tank satisfies the reference pressure condition, the controller opens the first port and the second port and closes the third port.

6 . The fuel cell system of claim 5 , wherein, when the second port is opened, the controller controls a duty of the first hydrogen supply valve to 100% and adjusts the duty according to a hydrogen supply state.

7 . The fuel cell system of claim 1 , wherein the first hydrogen supply valve comprises a solenoid valve.

8 . The fuel cell system of claim 3 , wherein, when the state of the hydrogen tank does not satisfy the reference pressure condition, the controller closes the second port and opens the third port.

9 . The fuel cell system of claim 8 , wherein, when the second port is closed, the controller controls a duty of the first hydrogen supply valve to 0%.

10 . The fuel cell system of claim 8 , wherein, when the third port is opened, the second hydrogen supply valve adjusts the pressure of the hydrogen to the constant pressure and supplies the pressure-adjusted hydrogen to the fuel cell stack.

11 . The fuel cell system of claim 1 , wherein the second hydrogen supply valve comprises a constant pressure regulating valve.

12 . The fuel cell system of claim 10 , wherein, when the hydrogen is supplied through the second hydrogen supply valve, the controller operates in a low output hydrogen constant pressure mode and transmits a load decrease request signal to a vehicle controller of a flight vehicle employing the fuel cell system.

13 . The fuel cell system of claim 12 , wherein, when operating in the low output hydrogen constant pressure mode, the controller initiates an emergency landing using the vehicle controller.

14 . The fuel cell system of claim 13 , further comprising:

a high-voltage battery configured to be charged by power generated by the fuel cell stack during the emergency landing.

15 . The fuel cell system of claim 14 , wherein the high-voltage battery supplies driving power to the flight vehicle during the emergency landing.

16 . The fuel cell system of claim 13 , wherein, responsive to a completion of the emergency landing, the controller outputs a message requesting charging of the hydrogen tank.

17 . A processor-implemented method, the method comprising:

identifying a state of a hydrogen tank during an operation of a fuel cell stack powered by hydrogen from the hydrogen tank; and

controlling a supply of the hydrogen to one of a first hydrogen supply line comprising a first hydrogen supply valve configured to variably adjust a hydrogen supply pressure and a second hydrogen supply line comprising a second hydrogen supply valve configured to adjust the hydrogen supply pressure to a constant pressure, according to the state of the hydrogen tank.

18 . The method of claim 17 , wherein the identifying of the state of the hydrogen tank comprises:

determining whether a reference pressure condition of the hydrogen tank is satisfied when an internal pressure of the hydrogen tank exceeds a reference pressure or a state of fuel (SoF) of the hydrogen tank exceeds a reference value when the internal pressure and the SoF of the hydrogen tank are identified.

19 . The method of claim 18 , wherein the controlling of the supply of the hydrogen comprises:

controlling the supply of the hydrogen through the first hydrogen supply line when the state of the hydrogen tank satisfies the reference pressure condition.

20 . The method of claim 18 , wherein the controlling of the supply of the hydrogen comprises:

controlling the supply of the hydrogen through the second hydrogen supply line when the state of the hydrogen tank does not satisfy the reference pressure condition.

21 . The method of claim 20 , wherein, responsive to the state of the hydrogen tank not satisfying the reference pressure condition:

operating in a low output hydrogen constant pressure mode when the hydrogen is supplied through the second hydrogen supply line;

guiding an emergency landing of a flight vehicle employing the fuel cell stack;

charging a high-voltage battery using power generated by the fuel cell stack while the emergency landing of the flight vehicle is attempted; and

supplying driving power from the high-voltage battery to the flight vehicle.

22 . A processor-implemented method, the method comprising:

controlling, responsive to a determined state of the hydrogen tank, a first port through which a supply of hydrogen being supplied from a hydrogen tank is introduced;

controlling, responsive to the determined state of the hydrogen tank, a second port configured to adjust a pressure of the hydrogen introduced through the first port and discharge the pressure-adjusted hydrogen through a first hydrogen supply line to a fuel cell stack;

controlling, responsive to the determined state of the hydrogen tank, a third port configured to adjust the pressure of the hydrogen introduced through the first port and discharge the pressure-adjusted hydrogen through a second hydrogen supply line to the fuel cell stack; and

entering a low output hydrogen constant pressure mode responsive to the determined state of the hydrogen tank not satisfying a reference pressure condition, the low output hydrogen constant pressure mode comprising:

controlling the third port to supply the hydrogen through the second hydrogen supply line; and

charging a high-voltage battery using power generated by the fuel cell stack.

23 . The method of claim 22 , wherein the low output hydrogen constant pressure mode further comprises initiating an emergency landing of a flight vehicle receiving power from the fuel cell stack.

24 . The method of claim 22 , wherein the low output hydrogen constant pressure mode further comprises supplying driving power to a flight vehicle employing the fuel cell stack using the high-voltage battery.