Conversores CC-CA matriciais indiretos multiníveis trifásicos com isolação galvânica NPC e tipo-T.

Abstract

An application of photovoltaic systems commonly used is pumping water for irrigation. In this task, the panels are responsible for feeding a motor that drives the hydraulic pump. For power an induction motor, direct voltageproduced by the photovoltaic system must be converted to alternating via a DC/AC converter (inverter). The most popular DC/AC converter topologies frequently disseminated in the literature employ electrolytic capacitors on their DC buses. Those types of capacitors have device life. O The present work proposes two new topologies based on multilevel converters with neutral point stapled (Neutral Point Clamped) and Type-T. THE difference from the proposed configurations to the ones already found in the literature is the possibility of remove the typical electrolytic capacitors in the DC bus of these inverters. For this, a profile voltage in pulses is generated on the bus and, from a pulse width modulation strategy (Pulse Width Modulation) it is possible to obtain the alternating currents demanded in the coils of the induction machine stator. In addition to the absence of electrolytic capacitors on the DC bus, another advantage presented by the proposed topologies is that the PWA strategy allows only one key pair of the circuit is switched by switching periods. Thus, switching losses tend to bereduced compared to traditional techniques. In in order to validate the theory explained, simulations computations were carried out to observe the operation of each of the proposed topologies. In addition, a 2kW propotype was used to obtaining the experimental results only with theNPC topology.