A Novel Multilevel Ac–Dc-Ac Converters with Improved Efficiency

Multilevel inverter technology has emerged recently as a very important alternative in the area of high power medium-voltage control and also for improving the total harmonic distortion by reducing the harmonics. Generally, the poor quality of voltage and current of a conventional inverter fed induction machine is obtained due to the presence of harmonics and hence there is a significant level of energy losses. The nine level inverter and seven level inverter are used to reduce the harmonics. So, this paper presents the simulation of three phases nine level inverter. In inverters by increasing the number of steps it generates the very high quality of the output voltage and current. This paper presents a nine level multi-level inverter and these can follow a voltage reference with accuracy and with the advantage that the generated voltage can be modulated in amplitude instead of pulse-width modulation. To operate effectiveness of proposed topologies, a level-shifted pulse width modulation (LSPWM) technique is presented and simulation results are verified for the operating stages of the proposed &9L converter. And a novel multilevel ac/dc/ac converter with reduced number of semiconductor devices to achieve light weight, efficiency, and better input currentquality. Comparative studies are conducted to analyze the performances of the two proposed front-end rectifiers and simulation results are presented by using Mat lab/Simulink environment.