Thermal Stress Analysis and MPPT Optimization of Photovoltaic Systems

In the last years, the optimization of the energy harvesting of photovoltaic systems during fast variable irradiance conditions has been an active area of research and of competition among the companies. The proposed fast maximum power point tracking (MPPT) algorithms can produce extremely variable loading of the power semiconductors resulting in a decrease of the system lifetime, which in consequence can nullify the economic advantage of higher energy harvesting. This work analyzes the problem with a deep theoretical and laboratory work. Then, a multiobjective MPPT, which limits the positive temperature gradient and the maximum junction temperature of the power semiconductors, is introduced and fully validated in the laboratory with a mission profile emulating variable irradiance conditions.