Simscape Fuel Cell - unexpected behavior

Good morning, I am trying to use the Fuel cell block in the Simscape environment with model fidelity sets on Simplified - nominal conditions.

I implemented a simple code to check the right behavior of the system. In particular, I compared the analytical polarization curve and the polarization curve obtained by Simscape measuring the fuel cell voltage and the current. I used a variable resistor to set the working conditions.

I would like to understand why there is this difference.

close all

clear

clc

%% Parameters

Eoc = 65; %[V]

A = 0.23; %[V]

N_unit = 10;

i0 = 80; %[A]

N = 65;

Ri = 0.05; %[Ohm]

ifc = linspace(0,300,1e3);

E = Eoc - N*A*log(ifc/i0);

vfc = N_unit*E-Ri*ifc;

%% Simulation

sim("FCsimscapeModel.slx")

%% Plot

figure, plot(ifc,vfc,'LineWidth',2), grid on, grid minor, hold on

plot(ans.current.Data, ans.voltage.Data, '--','LineWidth',2)

axis([0 300 0 1600])

legend ('Analytical polarization curve', 'Simscape polarization curve')

Answer 1

[Sabin]

We are aware of this behaviour which is cause by a small internal resistance used for protection. This will result in a small voltage drop. The workaround would be to measure the internal voltage using a Probe block rather than measuring with a voltage sensor. This will be corrected in future releases.