Dynamic Behavior of a Class of Photovoltaic Power Systems

An important consideration in the operation of grid connected photovoltaic power systems is a means of adjusting the photovoltaic array voltage so that maximum output power is achieved for the given atmospheric conditions. The dynamic behiavior of a specific photovoltaic power system which utilizes the well known perturb and observe method of power tracking is examined. Using measured insolation data, it is demonstrated that the perturb and observe method of control migrates considerably from peak power whenever the insolation varies randomly as a result of cloud cover. An alternate method of power tracking is also examined. It is shown that the photovoltaic power system, utilizing the proposed method of power tracking, is able to track accurately peak power conditions during periods of randomly varying insolation.