Automatic Parameters Calculation of Controllers for Photovoltaic dc/dc Converters

Abstract

Abstract. In the photovoltaic (PV) systems, the main objective of the control strategy is to extract the maximum power from the source; usually such objective is obtained by combining the action of the MPPT algorithm with a voltage regulator used to attenuate the disturbances at the source terminals. This work proposes an automatic procedure for designing the parameters of the voltage compensation network by solving a set of two nonlinear equations in which, the system phase and gain margins are previously assigned. The method is based on the modeling of the complete PV system (source, converter and load) and takes into account the main parasitic components also. Thanks to this global approach, the design of control strategies to regulate the PV panel output voltage can be optimized. The method has been theoretically analyzed and validated by using PSIM simulations. The designed voltage control loop has been tested also together with a P&O MPPT algorithm in order to regulate the PV voltage in a double stage grid-connected inverter in presence of a wide voltage oscillation at the DC-bulk and with fast irradiance variation.