In this study, a photovoltaic (PV) system is proposed with a capacitor directly connected between a PV module and a power converter. In the proposed system, the electrical energy output by the PV module is increased by receiving the discharge power of the additional capacitor without any losses other than itself and thus compensating for reduced power output when the intensity of the solar radiation decreases. However, the additional capacitor reduces the speed with which the operating point of the PV system can vary, which causes the conventional hill-climbing method to fail to track the maximum power point (MPP). Therefore, a modified hill-climbing method is also proposed that makes no errors in searching for the MPP. The proposed approach creates reference values based only on the difference in the output power of the PV module due to the variation in the operating point by correcting for fluctuations in the intensity of solar radiation. This allows the PV operating point to track to the MPP. The results of an experimental evaluation and a simulation show that the proposed method improved the output electrical energy of a PV system by 7.50% compared to the conventional method on a sunny day. Moreover, it also improved the output electrical energy of the system by 44.5% on a cloudy day.
Hattori et al. (Thu,) studied this question.