Técnicas de modulação para dois tipos de inversores de três níveis: balanceamento no ponto neutro, cálculo de perdas e redução no número de componentes.

Abstract

This dissertation presents a study for modulation strategies for three-level inverter (NPC and NRC). The main goals of these techniques is t o control the balance of the l i n k - DC voltages. I n order to obtain a better yield for the three-level inverter has been proposed a survey of the P W M modulation techniques PWM for these structures, highlighting its special and performing an analysis on some performance parameters. I n addition t o the techniques, this paper proposes a technique which is a combination of two another techniques. Moreover, this work proposes a general closed loop control. The analyzes were performed i n open-loop and closed-loop. The techniques were also analyzed w i th a considerably low switching frequency and also in order to implement a fairer comparison between the techniques, the average switching frequency is fixed. Are presented i n this paper, simulation results and some experimental. To test the strategies, the structure C A / C C / C A was built, where apart is a rectifier comprises for bridge diode. And another part is a multilevel inverter was made, the tow topologies (NRC and NPC) using the module from SEMIKRON . We also used a digital signal processor for generating the control signals and the fiber-optic devices, to avoid interference.