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represent a boost DC/DC converter, followed by a DC/AC converter, linked to the grid through a transformer. In isolated Systems it can represent a pure resistive load (heating) or a resistive-inductive load (motor), for example. In any case, the density of current of the celi, J (A/cm²), is defined by the following expression:

J = ^ljZ-    (15)

A

The instantaneous electrical power supplied by the celi to the load can be determined by the eąuation:

^fc ⁼ ^fc-‘fc    (1^)

where Vfc is the celi output voltage for each operating condition, Eq. (4), and Pfc is the output power, in Watts.

The FC efficiency can be determined from the eąuation [9]:

(17)

V_K

ri = p_r.-^ ¹ 1 1

where fjf is the fuel utilization coefficient, generally in the rangę of 95%, and 1.48 V represents the maximum voltage that can be obtained using the higher heating value (HHV) for the hydrogen enthalpy. Fuel utilization is assumed to be constant, which is valid where the fuel celi has a hydrogen flow ratę control. In this case, the hydrogen is supplied according to the load current.

IV. SIMULATION RESULTS