PROJECT TITLE :

Stable operating area of photovoltaic cells feeding DC–DC converter in output voltage regulation mode

ABSTRACT:

From the perspective of output voltage management stability, this study investigates the stable operating area of photovoltaic (PV) cells feeding the DC–DC converter in output voltage regulation (OVR) mode. During this study, the boost interface converter is taken as an example, and its management system arrangements, tiny-signal model including the dynamic equivalent circuit of PV cells and also the closed-loop transfer functions with totally different management loop formation are deduced at 1st. After that, according to the Hurwitz criterion, the essential condition for output voltage control stability is analysed and therefore the relations between control loop formation of the interface converter in OVR mode and also the stable operating space are obtained. The validity of the theoretical analysis has been verified by the experiment and simulation results of a a hundred and fifty W prototype. The investigation shows that: (i) no matter what kind of management loop formation is adopted, the PV cells cannot output the maximum power when the PV interface converter operates in OVR mode; (ii) when the interface converter operates in OVR mode, PV cells can only operate stably in voltage area or current space. Moreover, the type of operating area entirely depends on the converter's output voltage management loop formation.