Sistemas de conversão de energia baseados em conversores estáticos de potência monofásicos do tipo CA-CC-CA.

Abstract

Concerning the power quality, static converters are a tool widely used in power systems. In this dissertation, five topologies of converters AC-DC-AC are studied, two of them do not use transformer and have two DC-links, the other three use a transformer and have a single DC-link. One of the converters studied already was mentioned in the technical literature. This work gives a different approach from the perspective of the control and definition of the PWM strategy. The following aspects are discussed for each topology: (i) dynamic modelling; (ii) PWM strategy; (iii) control of several variables of the system, i.e., input grid current (waveform and power factor), DC-link voltage, load voltage; (iv) characterization of the converters based on harmonic distortion of voltages and currents and conduction and switching losses of the semiconductor switches. For topologies that have two DC-links, is explored the possibility of operation with different voltages in the DC-links in order to improve the performance of these structures. For the topologies that use transformer, the optimization their performance is done through the appropriate choice of this component (choice of transformation ratio). The converters are suitable for applications that operate with the same frequency in the input and output (e.g., uninterruptible power supply - UPS), voltage regulated sources, harmonic compensators, etc). In order to validate the studies performed in this work, results were obtained from simulations and experimental tests.