QUEIROZ, A. P. D.; DE P. D. QUEIROZ, A.; Queiroz, A. de P. D.; http://lattes.cnpq.br/4815546993617747; QUEIROZ, Antonio de Paula Dias.
Resumo:
Static converters are a valuable tool when seeking to improve the power quality of power
systems. This work presents conventional and proposed converters, all composed by AC-DC
(or DC-AC) and AC-DC-AC modules with two or three legs without isolation transformer.
We studied two types of converters: fourteen single-phase converters, derived from series
and/or parallel connection of AC-DC modules with two legs, and eight AC-DC-AC converters
obtained from AC-DC-AC modules with three legs. 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 and low frequency of the circulating current (when it exist); (iv) characterization
of the converters based on harmonic distortion of voltages and currents, losses of the DC-
link capacitors, and conduction and switching losses of the semiconductor switches. The
series connection is advantageous because they allow the reduction of the DC-link voltage,
the harmonics generated by the converters, witch reduce the rating of the semiconductor
switches. The parallel connection is advantageous because they reduce the currents, power
and harmonics of leg converters. In order to reduce voltage and current of the semiconductor
switches, this work to propose building static converter by series and parallel connections.
In order to validate the results, simulation and experimental results are presented.