Modeling and simulation of a novel multilevel inverter for PV systems using unequal DC sources

Multilevel inverters (MLI) offer high power capability, allied with lower commutation losses and lower output harmonics. Their main drawback is their complexity, requiring a great number of power devices. This effort initiates a new multilevel inverter topology using an H-bridge output stage with the modular type structure. The new topology provides a significant reduction in the number of power devices and voltage sources required to implement a multilevel output. The proposed multilevel inverter structure consists of two basic parts. The parts are classified as Level and H-Bridge Modules. The most extraordinary feature of the system is its ease of extension. By increasing the number of level modules and connecting them cascaded, the inverter system can expand and the voltage level number can be easily increased. The Level Module consists of a semiconductor switching devices, a diode and a dc source. Unequal DC sources in the proposed MLI gives higher output voltage and economic result. Modeling and Simulation of proposed MLI is done using MATLAB-Simulink. Harmonic analysis is done with Super Imposed Carrier Pulse Width Modulation (SICPWM).