Compensadores estáticos de potência para sistemas trifásicos.

Abstract

In this doctoral work is treated of power static compensators (or active power filters) three-phase systems and techniques for improving power quality associated with emphasis on the most appropriate employment of each. Specifically, we can highlight two issues at work: the analysis of behavior in compensating the steady state, seeking to optimize the design and operation of these new topologies and study. Series, Shunt and universal active power filters are studied, however the main focus is the latter. The universal active power filters is analyzed in three different proposed implementation of: i) the classical - a converter of six arms and a bus dc, ii) a converter five arms, and a bus dc, iii) with two three-phase converters and two buses dc and iv) three-phase converters and three dc buses . The steady state analysis for shunt and series active power filters allows a better understanding of the operation and optimization of the universal filter, which is simply the joining of these two. In this analysis it is possible to modify all the system parameters, in order to appreciate the behavior of currents and voltages ratings, seeking an operating point that minimizes the converter power loss. The implementation of the universal filter with two dc bus is justified by the fact that each filter individually requires a different dc bus voltage, this way the dc bus voltage of each filter can be designed better. A lower dc bus voltage improve total harmonic distortion and reducing converter power losses. In five-leg universal active power filter topology (with one dc bus). The voltage capability of dc bus is analysed, looking for situations where synchronism is between the voltages, since in this situation the five-leg converter has the same dc bus voltage capability of a six-leg converter. Probably, because of unless there is a leg, maybe occur a reduction of power losses in the converter. Finally proposals are two topologies that employ three-phase converters without the sharing of dc bus voltage. One uses two shunt and one series active power filter, that will be called as a universal filter shunt-series-shunt. The other topology will be called xv xvi series-parallel-series, because it uses two series and one shunt active power filter. These topologies have a disadvantage of using a lot of semiconductor switches, dc bus capacitors, however they have a degree of freedom that is used for system optimization. For comparison between the structures was used as a basis, the switching losses, conduction and blockade of the semiconductor switches. In this sense in the time domain simulations have also been developed for the topologies in order to assess such losses. The work has the merits a more detailed description of the behavior of active filters series, sunht and universal, thus presenting the best operating points of the same, and present different ways of implementing the universal filter.