Power optimization of photovoltaic modules under varying environmental conditions based on current equalization collaborating with constant voltage control

Abstract

Abstract The performance of photovoltaic (PV) modules is affected by environmental factors such as irradiance and temperature, which can lead to a decrease in output performance or even damage. This study proposes an improved formula for calculating the real maximum power of PV modules by analysing the influence of irradiance and temperature. A simulation model is developed using PLECS software to simulate the global maximum power of PV modules under different environmental conditions and the results are compared with the calculated real maximum power. A power optimization scheme for PV modules is then proposed based on current equalization and constant voltage control. This scheme employs a single-switch multi-winding forward–flyback converter to equalize the mismatched currents between cell strings, thereby enhancing the output performance. Traditional proportional–integral controllers are utilized to achieve constant voltage control and obtain the real maximum power of PV modules. Simulation models are built in the PLECS simulation platform to evaluate the performance of a global maximum power point tracking scheme based on the traditional perturb-and-observe (TPO) algorithm with current equalization, a segment perturb-and-observe algorithm without current equalization, and the proposed power optimization scheme. The simulation results demonstrate that the proposed constant voltage control has greater efficiency than the TPO algorithm. The proposed scheme achieves a significant improvement in efficiency, with a 27.87% increase compared with the segment perturb-and-observe algorithm without current equalization.