Conversor CA-CC-CA monofásico-monofásico: modulação PWM e controle.

Abstract

In this work, it is presented and discussed a single-phase rectifier-inverter composed of two three-arm converters with unequal DC-links and connected in series. These converters are made with controlled switches, i.e., IGBT transistors. The fact that these converters present unequal DC-links increases the number of voltage levels and contributes to reduce the harmonic distortion and the switching frequency. The balance of separated DC sources is a problem addressed in this work. A feedforward controller is used to control the average value of the DC voltages. In order to control the DC-links individually, a hysteresis control combining space-vector PWM and an adapted version of Level-Shifted PWM is applied. Therefore, it is discussed and explained the system model, scalar, space-vector and Level- Shifted PWM techniques applied on the converters switching, the control strategies and diagrams, and finally it is done the comparative analysis between proposed and convencional systems in terms of cost and quality, taking the simulation results as basis.