Dynamic Behavior of a Class of Photovoltaic Converters

摘要

The perturb and observe peak power tracker operates by periodically incrementing or decrementing the array voltage. If a given perturbation leads to an increase or decrease in array power, the subsequent perturbation is made in the same or opposite direction respectively. Thus the peak power tracker continuously hunts or seeks peak power conditions. The dynamic behavior of a specific photovoltaic design which utilizes the perturb and observe method of peak power tracking is discussed. It is shown that when the insolation does not vary with time, the perturb and observe method is able to converge to peak power conditions; however, when the insolation varies randomly at any substantial rate, the perturb and observe method fails to adequately track the peak power conditions. An alternate method of power tracking is examined which utilizes the harmonic components of the array voltage and current to establish proper control action. The performance of this method as compared to the perturb and observe method is demonstrated using a detailed hybrid simulation of the photovoltaic system. The design of the photovoltaic system and the detailed simulation of the various system components are described. (ERA citation 07:056566)