Method and system for diagnosing fuel cell stack

A method for diagnosing a fuel cell stack, comprising:

• determining, by a controller, whether a variance of an output current of the fuel cell stack is less than a predetermined variance, whether diagnosing of the fuel cell stack is required, and whether a motor controller and a power conversion controller are in a normal state;
• transmitting, by the controller, to the motor controller instructions for initiating a fuel cell stack diagnosis based on a result of the diagnosis determination, and stopping an operation of the power conversion controller, the instruction being for driving a motor adjusted to a first efficiency value during a predetermined first reference time period;
• when the predetermined first reference time period has elapsed, transmitting, by the controller, to the motor controller instructions for terminating a fuel cell stack diagnosis to drive the motor adjusted to a second efficiency value, and resuming the operation of the power conversion controller;
• and
• diagnosing, by the controller, a state of the fuel cell stack based on a voltage variance of the fuel cell stack between when driving the motor adjusted to the first efficiency value and second efficiency value.

A system for diagnosing a fuel cell stack, comprising:

• a fuel cell controller configured to diagnose a state of the fuel cell stack by determining a time when diagnosing a fuel cell stack is required based on a plurality of factors;
• and
• a motor controller configured to drive a motor adjusted to a first efficiency value for a predetermined first reference time period based on a result of the diagnosis determination, drive the motor adjusted to a second efficiency value when the first reference time period has elapsed, and transmit to the fuel cell controller a resistance value analyzed based on a voltage variance of the fuel cell stack between driving the motor adjusted to the first efficiency value and second efficiency value,
• wherein the fuel cell controller is configured to diagnose a state of the fuel cell stack based on the transmitted resistance value.

A non-transitory computer readable medium containing program instructions executed by a controller, the computer readable medium comprising:

• program instructions that determine a time at which diagnosing a fuel cell stack is required based on a plurality of factors;
• program instructions that drive a motor adjusted to a first efficiency value during a predetermined first reference time period from the time of diagnosis determination;
• program instructions that drive the motor adjusted to a second efficiency value after the first reference time period has elapsed;
• and
• program instructions that diagnose a state of a fuel cell stack based on a voltage variance of the fuel cell stack between driving the motor adjusted to the first efficiency value and second efficiency value.