Distributed maximum power point tracking in photovoltaic systems-emerging architectures and control methods

The interest in distributed maximum power point tracking increases along with increasing deployment of photovoltaic generators and the constant pressure to reduce the cost of photovoltaic generated energy. Distributed maximum point tracking facilitates a significant boost of captured photovoltaic power. In this paper we compare different distributed maximum power point architectures, and categorize them into two main groups; those which process the entire generated power and partial power processing based architectures. The first ones are found to be easier to control while the second ones exhibit higher efficiency. Some delicate control issues are emphasized; a distinction is made between maximum power point tracking and negative feedback control. For systems consisting of multiple power processors, we derive the required number of maximum point tracking units and their adequate location within a global architecture. Only the right number of units guarantees extraction of the entire potential power as well as system stability. In contrary, we demonstrate how instability occurs due to a redundant control structure.