Distributed MPPT control under partial shading condition

Abstract

The performance of series connected PV panels significantly limited by the current mismatch caused by the partial shading. Distributed maximum power point tracking can increase the overall efficiency. A module level and a string level sub-module integrated maximum power point trackers are presented in this thesis. The module level version is supposed to be applied for high power PV modules. For low power PV modules or strings, the string level trackers are recommended. The application cost of the string level MPP trackers is limited by mounting the size minimized synchronous buck converters directly into the junction boxes on the back of the PV panels. Two steps hill climbing method is applied to track the MPP of each sub-module by sampling and maximizing the output voltage of each sub-module. The global MPP relies on the inherent MPP tracking function of the output side connected inverter. Through the simulation of the system built in Simulink, the feasibility is verified fist. Then the performance of proposed architecture is tested through experiment.