System and method of controlling air compressor motor for fuel cell vehicle and system and method of controlling operation of fuel cell vehicle using same

1. A method of controlling an air compressor motor for a fuel cell vehicle, comprising:

calculating, by a controller, a counter electromotive force constant of the air compressor motor based on a voltage and a current of the air compressor motor for the fuel cell vehicle supplying air to a fuel cell stack and a rotation speed of the air compressor motor; and

determining, by the controller, whether a permanent magnet of the air compressor motor is demagnetized based on a result of comparison between the calculated counter electromotive force constant and a pre-set counter electromotive force constant design value.

2. The method of claim 1 , wherein, in the calculating of the counter electromotive force constant, a three-phase voltage and a three-phase current of the air compressor motor are converted into voltages of d and q axes and currents of d and q axes, respectively, and the electromotive force constant of the air compressor motor is calculated by applying the converted voltage of d and q axes, and an electric angular velocity of the air compressor motor to the motor equation.

3. The method of claim 2 , wherein the electromotive force constant of the air compressor motor is calculated using a following equation:

V

dsyn

=

R

s

×

I

dsyn

+

L

d

×

d

⁢

I

dsyn

dt

-

L

q

×

ω

e

×

I

qsyn

⁢

V

qsyn

=

R

s

×

I

qsyn

+

L

q

×

d

⁢

I

qsyn

dt

+

L

q

×

ω

e

×

I

qsyn

+

V

emf

Equation

where, since V emf =λ×ω e , then λ=V emf /ω e

wherein, V dsyn is the voltage of the d-axis of the air compressor motor, and V dsyn is the voltage of the q-axis of the air compressor motor, I dsyn is the current of the d-axis of the air compressor motor, I qsyn is the current of the q-axis of the air compressor motor, R s is a phase resistance of the air compressor motor, L d is a inductance value of the d-axis of the air compressor motor, L q is an inductance value of the q-axis of the air compressor motor, ω e is the electric angular velocity of the air compressor motor, V emf is a counter electromotive force voltage of the air compressor motor, and is the calculated counter electromotive force constant.

4. The method of claim 1 , wherein when the air compressor motor operates in a normal state, the counter electromotive force constant is calculated.

5. The method of claim 1 , wherein when demagnetization is detected in the permanent magnet of the air compressor motor, the method further includes:

calculating, by the controller, a maximum drivable speed that the air compressor motor is capable of outputting in a demagnetized state using the calculated counter electromotive force constant and the voltage and current of the air compressor motor.

6. The method of claim 5 , further comprising:

compensating, by the controller, a beta angle map for adjusting a weak field magnet based on the maximum drivable speed of the air compressor motor in the calculated demagnetized state.

7. A method of controlling an operation of a fuel cell vehicle; comprising:

calculating, by a controller, a counter electromotive force constant of an air compressor motor based on a voltage and a current of the air compressor motor for the fuel cell vehicle supplying air to a fuel cell stack and a rotation speed of the air compressor motor;

determining, by the controller, whether a permanent magnet of the air compressor motor is demagnetized based on a result of comparison between the calculated counter electromotive force constant and a pre-set counter electromotive force constant design value;

calculating, by the controller, a maximum drivable speed that the air compressor motor is capable of outputting in a demagnetized state using the calculated counter electromotive force constant and the voltage and current of the air compressor motor;

calculating, by the controller, an air supply limit that is an amount of air capable of being supplied to the fuel cell stack by the maximum drivable speed that the air compressor motor is capable of outputting in the demagnetized state; and

limiting, by the controller, an output of the fuel cell stack to a level equal to or less than an output of the fuel cell stack corresponding to the air supply limit.

8. The method of claim 7 , further comprising:

confirming, by the controller, a state of charge of the energy storage device that provides power to a driving motor of the fuel cell vehicle after limiting the output of the fuel cell stack; and

limiting, by the controller, an oscillation performance of the fuel cell vehicle by limiting a current supplied to the driving motor of the fuel cell vehicle when the state of charge of the energy storage device is insufficient.

9. A system of controlling an operation of a fuel cell vehicle, comprising:

a memory configured to store program instructions; and

a processor configured to execute the program instructions, the program instructions when executed configured to:

calculate a counter electromotive force constant of an air compressor motor based on a voltage and a current of the air compressor motor for the fuel cell vehicle supplying air to a fuel cell stack and a rotation speed of the air compressor motor;

determine whether a permanent magnet of the air compressor motor is demagnetized based on a result of comparison between the calculated counter electromotive force constant and a pre-set counter electromotive force constant design value;

calculate a maximum drivable speed that the air compressor motor is capable of outputting in a demagnetized state using the calculated counter electromotive force constant and the voltage and current of the air compressor motor;

calculate an air supply limit that is an amount of air capable of being supplied to the fuel cell stack by the maximum drivable speed that the air compressor motor is capable of outputting in the demagnetized state; and

limit an output of the fuel cell stack to a level equal to or less than an output of the fuel cell stack corresponding to the air supply limit.

10. The system of claim 9 , wherein the program instructions when executed are further configured to:

confirm a state of charge of the energy storage device that provides power to a driving motor of the fuel cell vehicle after limiting the output of the fuel cell stack; and

limit an oscillation performance of the fuel cell vehicle by limiting a current supplied to the driving motor of the fuel cell vehicle when the state of charge of the energy storage device is insufficient.