This paper presents a high performance, Zsource inverter topology for grid connected PV systems and also Synchronized Pulse-Width Modulation technique in single and three phase PWM inverter for Photovoltaic power generation system. Z -source inverter has buck-boost feature, which is possible because of additional shoot through state introduced in zero state of the conventional pulse width modulated inverter and provides desired output ac voltage. The two independent control variables, the shoot-through duty ratio and the modulation index are used to control the proposed system in order to provide the required voltage and power. Simulation of single and three phase system is carried out using MATLAB/SIMULINK package and the results are presented for Z -source inverter.

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This work aims at improving the dynamic performance of the available photovoltaic (PV) system and maximizing the power obtained from it by the use of cascaded converters with intelligent control techniques. Fuzzy logic based maximum power point technique is embedded on the first conversion stage to obtain the maximum power from the available PV array. The cascading of second converter is needed to maintain the terminal voltage at grid potential. The soft-switching region of three-stage converter is increased with the proposed phase-locked loop based control strategy. The proposed strategy leads to reduction in the ripple content, rating of components, and switching losses. The PV array is mathematically modeled and the system is simulated and the results are analyzed. The performance of the system is compared with the existing maximum power point tracking algorithms. The authors have endeavored to accomplish maximum power and improved reliability for the same insolation of the PV system. Hardware results of the system are also discussed to prove the validity of the simulation results.

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