New Fuzzy Control of Photovoltaic Conversion Cascade Based Three Levels Inverter for Stand-Alone Applications

This paper presents a new control scheme based on Fuzzy Logic Controller (FLC) of output three levels inverter voltages for photovoltaic conversion stand alone two stages cascade. The error between the root mean square value of output voltage and it to reference and the change of error constitute the two inputs of FLC. The error of modulation index represents the output of FLC. The boost converter is controlled by a FLC in order to extract the maximum power from PVG. In order to have a symmetrical and stable output voltage of our cascade, the input DC voltages must be of equal values. An algorithm for stabilizing these two voltages using the redundant configurations of the inverter vectors is introduced into the control loop. The simulation results show that the rms output voltage is inside the band of +/-10V and with low total harmonic distortion despite irradiation change.