Projeto de um inversor de tensão VSI para um sistema pseudo UPS-senoidal e carga resistiva

Abstract

This work presents a contribution to the implementation of Distributed Generation of Electric Energy through the development of an AC voltage source that behaves as a pseudo UPS (uninterruptible power supply) - sinusoidal system that can evolve to a system of voltage supply connected to the grid . The sine-wave UPS system is a secondary power supply system that starts up in the event of a failure of the primary network. While there is power supply through the primary network, a process of converting the alternating voltage from the mains to DC is performed to power a bank of batteries. After the mains interruption, there is a process of reversing the continuous voltage levels of alternating batteries in order to feed the load. In this way, the load has voltage with amplitude and frequency totally independent of the input. The difference of this system to the developed in this work is in the fact that the primary source is not the network but an already continuous source and there is not the feeding of batteries. The main objective is the construction of an experimental platform capable of synthesizing a sinusoidal voltage whose frequency and voltage parameters are as close as possible to 60 Hz and 220 V RMS, respectively. The primary source of this system is a 24 V DC voltage source that goes through an inversion process so that a resistive load is fed at the end of the process. A low-pass LCR filter is designed and constructed to reduce the influence of switching noise from the inversion process. The control circuit is made by an ARM Cortex-M3 processor, shipped in an Arduino family device. The complete circuit formed by the power, controller and load part is modeled in order to be evaluated in a computer simulation platform.