ANALYSIS OF PWM STRATEGIES FOR Z-SOURCE CASCADED MULTILEVEL INVERTER FOR PHOTOVOLTAIC APPLICATIONS

MultiLevel Inverters (MLI) are of special interest in the distributed energy sources area because several batteries, fuel cell, solar cell and wind turbine can be connected through MLI to feed a load without voltage balance problems. The disadvantage of MLI is that its output voltage amplitude is limited to DC sources voltage summation. Therefore, a Z-source cascaded multilevel inverter for Photovoltaic (PV) system is proposed in this paper to achieve single energy conversion and boost function. The Z-source network in each module is immune to shoot-through faults when operating at high switching frequency and enhances the system reliability. This paper focuses on phase shifted sinusoidal PWM strategy implemented with simple boost control, maximum boost control and constant boost control for the proposed topology. The performance parameters such as total harmonic distortion (THD), inductor current ripple, capacitor voltage ripple, voltage gain and voltage stress. Simulations of the circuit configuration will be performed in MATLAB/SIMULINK and the results are verified.