Topologia de conversor CA-CA unidirecional três níveis trifásico com número reduzido de componentes.

Abstract

These days the loads are more and more non-linear and it causes load currents to be non-sinusoidal. The main will be damanged by the pulsant power fowing, and so the other loads. Diferent kinds of loads have been feeded by a alternade current main, through a direct convertion sistem (rectifiers, direct ac-ac converters) or indirect sistem (indirect ac-ac converter). These sistems are non-linear loads, witch generates non-sinusoidal main currents, damaging the utilization by the user. A way to minimize this bad efects is the use of active rectifiers, making the load current to be quasi-sinusoidal and reducting reactive power flowing on the main. And to ac loads, ca-ca converters must be used, where active rectifires, in the first stage, must sorve de inverter, in the second stage. At this way, the main will see always linear loads, and any load will be feeded by sinusoidal sources. This work proposes a ca-ca converter topology where a open-loop unidirection three level three phase reducted componenetes active rectifier is conected directly to a three level three phase convencional inverter. The converter is mained provide sinusoidal and THD reducted current in the rectifier entrance and THD reducted voltage provided by the inverter. The open-loop control on the rectifier provides also simplicity and the PWM proposes to the inverter let it free to use any conventional machine control schema. Is shown in this document theory analysis and simulation and experimental results to each stage of the converter operating in stand alone and to the complete converter.