Abstract: A system includes a fuel cell stack having a plurality of fuel cells and designed to receive a fluid and to heat the fluid. The system also includes an actuator to increase or decrease a fluid temperature of the fluid and an ECU. The ECU can determine a temperature control signal corresponding to a desired temperature of the fluid and perform a feedforward control of the actuator to increase or decrease the fluid temperature towards the desired temperature. The ECU can also determine a temperature difference between the fluid temperature and the desired temperature, and can determine a sensitivity that corresponds a change in a parameter value or the actuator position to a change in the fluid temperature. The ECU can also apply the sensitivity to the temperature difference to determine an error signal, and control the actuator based on the error signal.