Partial shading is one of the unfavourable conditions for photovoltaic modules since available power of them decreases. Besides that, maximum power point tracking becomes difficult in that kind of condition. Multiple maximum power points occur on the voltage - power curve of photovoltaic modules, if modules have bypass diodes. Hence, this paper proposes a new algorithm which provides fast and accurate tracking in partial shading conditions. It is shown that values of duty ratios change in limited range in partial shading which is approximately 40% in buck-boost converter topologies which is the major idea of the proposed algorithm. A few duty ratios, which are based on the number of bypass diodes, are calculated by using equivalent resistance of photovoltaic module which is ratio of voltage and current of a module. Then, these duty ratios are applied to the DC-DC converter. A single ended primary inductance converter (SEPIC) is modelled in MATLAB/Simulink, in order to validate the performance of the proposed algorithm. Simulation results show that proposed algorithm has capability of tracking global maximum power point in all partial shading conditions and it has simple structure which can make this algorithm applicable for commercial products.

32nd European Photovoltaic Solar Energy Conference and Exhibition; 2118-2122