Title :
Line current harmonics reduction in hybrid multilevel converters using phase-shifting transformers
Author :
Rech, C. ; Pinheiro, J.R.
Author_Institution :
Power Electron. & Control Res. Group, Santa Maria Federal Univ., Brazil
Abstract :
This paper proposes a new arrangement to implement the dc voltage sources of hybrid multilevel inverters in active power transfer applications, using only uncontrolled rectifiers and phase-shifted secondary windings. As each cell of a hybrid multilevel inverter usually processes distinct power levels, this paper then proposes a new design methodology to determine the phase shifts among the secondaries of the input isolation transformer, even when the active power levels processed by the uncontrolled rectifiers are unequal. A set of phase angles is obtained to minimize, and even to eliminate, desired low-order harmonics of the input current, in particular the fifth harmonic, since this harmonic component presents an amplitude considerably higher than the amplitude of the other harmonics. In consequence, the proposed design methodology increases the input power factor and reduces the input current THD. Simulation and experimental results are presented to demonstrate the feasibility of the proposed structure.
Keywords :
harmonic distortion; invertors; phase shifters; power convertors; power transformers; rectifiers; transformer windings; active power transfer applications; hybrid multilevel converter; hybrid multilevel inverters; input current THD; input isolation transformer; line current harmonic reduction; phase-shifted secondary windings; phase-shifting transformer; uncontrolled rectifiers; Active filters; Design methodology; Frequency; Inverters; Power harmonic filters; Power system harmonics; Rectifiers; Transformers; Variable speed drives; Voltage;
Conference_Titel :
Power Electronics Specialists Conference, 2004. PESC 04. 2004 IEEE 35th Annual
Print_ISBN :
0-7803-8399-0
DOI :
10.1109/PESC.2004.1355233