The impact of methanol concentration on direct methanol fuel cell (DMFC) of 45 cm 2 zones of activity was experimentally

studied with serpentine channel fi eld design. The performance of the DMFC was analyzed and the optimum methanol concentration

was determined with a polarization curve. A recently suggested Coeffi cient Diagram derived from PI Controller

(CD-PIC) was used to run the model-based DMFC in a closed loop with the manipulated variable as methanol concentration.

The CD-PIC design is simple and effi cient compared to the Bode Diagram-based controller design. It is also used to

test the performance and robustness of the system apart from the stability. A recently suggested PI Controller that relies on

a Coeffi cient Schematic is employed in DMFC operation. The progress of the proposed CD-PIC is evaluated under load

abandonment circumstances and set point monitoring. Set point tracking and load rejection tests are carried out with step

changes at diff erent operating points. The controller execution is evaluated in ways of controller progress measuring (CPM)

indices. The suggested performance metrics for the proposed CD-PIC indicate that it yields better performance for servo

problems and regulatory problems which support the supremacy of CD-PIC. The robustness of the CD-PIC is also analyzed.

From the CPM indices, it is concluded that the recently created CD-PIC for DMFC is found as highly robust.