SILVA, J. C. L.; http://lattes.cnpq.br/2988939366744118; SILVA, Juliano Costa Leal da.
Resumo:
This work studies the reduction of the total number of components in four
multilevel converters structures. This enables the simplification of modulation strategy
used to control the switches, reducing the cost of these converters, besides contributing
to the reduction of total electrical losses. They are discussed a total of eight single-phase
multilevel inverters, four of these are already known in the literature, called
conventional and the other four are proposed with the reduction of the conventional
switches, using inductors magnetically coupled between unidirectional complementary
legs. For each proposed converter it is discussed the operation and modulation strategy
employed. In quantitative terms, the inverters using the inductive coupling obtained
better relationship between the number of levels of the output voltage and the number of
topology switches, better harmonic performance and lower level of electrical losses in
semiconductors. Moreover, for the correct operation of these converters, it was
necessary to add a offset reference voltage in each leg so that the diodes in the legs
could conduct when a complementary switch is turned off. Also, it should be noted that
the reduction of semiconductors and magnetic element added in a multilevel converter
is only valid when any of the parameters of weight, volume and/or total cost of
converter is lower than the traditional multilevel converters and the relevance of these
parameters must be specified in converter design, according to its specific application.
To validate the proposed converters it’s presented the obtained simulation results and
some of the experimental tests performed in the Laboratory of Industrial Electronics and
Machinery Drive (LEIAM) belonging to the Federal University of Campina Grande
(UFCG).