Control of DC-DC converter in photovoltaic system using time-delay estimation

Because a conventional DC-DC converter system has small variation in the input voltage, it is sufficient to use Proportional-Integral (PI) controller with fixed gains. However, in Photovoltaic (PV) systems, the operating conditions such as irradiation and ambient temperature are time-varying. In these circumstances, when the operating conditions change abruptly or the uncertainties become large, the conventional PI controller cannot assure the best performance in controlling the DC-DC converter of PV systems. For the maximum power extraction from PV systems, in addition to the performance of Maximum Power Point Tracking Power module, that of DC-DC converter is also important. To enhance the control performance of the DC-DC converter in PV systems, a controller using time-delayed information is presented. The proposed controller intentionally utilizes time-delayed information of the given system and control input to eliminate the unknown system dynamics and unexpected disturbance. By doing these actions, the controller can show robust performance to the abrupt change in the operating conditions. Through computer simulation, the validity and effectiveness of the proposed controller are evaluated by comparing with conventional PI controller.