Análise e controle de um conversor CA-CC com elevado ganho de tensão aplicado a um sistema de geração de micro-ondas

Abstract

This master thesis performs the analysis and design of an AC-DC converter with high voltage gain to be used to supply a magnetron in a microwave generation system. The converter topology is chosen so as to enable input power control, operation with high power factor and with possibility of wide variation in the effective voltage input, so that the converter operates in the universal 100-240 V effective voltage range. The topology consists of a controlled type half-bridge rectifier at the entrance, responsible for the current control and diferencial voltage balance on the DC link capacitors and an isolated DC-DC half-bridge converter with high voltage gain, which operates with a fixed duty cycle. The design of passive and active elements of AC-DC converter are presented and the discrete control to implement a prototype that operates with input power up to 800 W is performed. The controllers are implemented in a low-cost 32-bit and fixed point arithmetic microcontroller. Experimental results to validate the designed controllers are obtained for various power reference values, evaluating the converter for practically all operational range.