Analyzes of Flyback DC-DC Converter for Submodule Level Maximum Power Point Tracking in Off-grid Photovoltaic Systems

Abstract

Submodule level maximum power point tracking (MPPT) systems have become popular due to its outstanding performance in partial shading conditions (PSCs) and basic algorithm requirement. MPPT is realized by DC-DC converters. They are power processing units between photovoltaic (PV) module and resistive load. Among DC-DC converter topologies, the flyback is a proper choice since it can either increase or decrease the voltage. Furthermore, power level is small in submodule level (SML) MPPT applications. In this study, analyzes and power circuit design of a flyback converter for continuous conduction mode (CCM) is carried out firstly. Then, the performance of the flyback converter on the SML MPPT system and its superiority over the module level MPPT is shown by using same converter topology and perturb and observe (P&O) algorithm. In order to validate the superior performance of SML MPPT, it is compared with module level MPPT in MATLAB/Simulink environment. Results show that SML MPPT guarantees global MPPT in any PSCs with any kind of basic MPPT algorithm. On the other hand, module level MPPT fails in many PSCs with the same algorithm. According to simulation results, SML MPPT generated more power by 61.2% in average than module level MPPT systems in simulation studies.