Research On Maximum Power Point Tracking Of PEMFC

PEMFC is ready for large-scale commercialization if its cost can be reduced. It seems to be one flexile way to make full use of the cell within its limited lifetime in current situation, which would be directly achieved by system performance improvement. There are some applications where power density is at a premium as compared with fuel efficiency, and the maximum power point tracking (MPPT) would be beneficial in such cases.It is the precondition for system performance improvement to get familiar with the cell characteristics. Over the foundation of thermodynamic property and kinetic model, experiments for testing the basic characteristics of the fuel cell were firstly designed and accomplished, based on the test bench set up with a home-made PEMFC and other related equipment, corresponding analysis and comparison about the I-V curve fitted by the static and dynamic testing data were made.Improved options should be given out by actual demand. With the theory of water and thermal management, comprehensive applied experiments were implemented to investigate the influence of operating conditions such as purge process, fan voltage and short-circuit on the system output. Experiment with the inflow of pulsating hydrogen was introduced to verify its effects on the system performance improvement. Thereby, improved measures available to the lab system were put forward.According to the concept and principle of MPPT, three algorithms were introduced in view of the home-made cell, which were open-circuit voltage method, perturbation and observe method and resistance incremental method. The principle, procedure, effect of the different tracking were analyzed and compared, the inadequacy and applicability for their practical use were summarized.Finally, the simulation models of the three MPPT methods were established respectively, and were all realized on Matlab/Simulink software. By selection calculation of DC/DC circuit and integration of Buck convertor for adjusting duty ratio, SCM for programming control algorithm and sampling circuit for converting signal, MPPT controller was preliminary designed.