ABSTRACT:
This paper presents a new family of buck type PFC
(power factor corrector) rectifiers that operates in CCM (continuous conduction
mode) and generates multilevel voltage waveform at the input. Due to CCM operation,
commonly used AC side capacitive filter and DC side inductive filter are
removed from the proposed modified packed U-cell rectifier structure. Dual DC
output terminals are provided to have a 5-level voltage waveform at the input
points of the rectifier where it is supplied by a grid via a line inductor.
Producing different voltage levels reduces the voltage harmonics which affects
the grid current harmonic contents directly. Low switching frequency of the
proposed rectifier is a distinguished characteristic among other buck type
rectifiers that reduces switching losses and any high switching frequency
related issues, significantly. The proposed transformer-less, reduced filter
and multilevel rectifier topology has been investigated experimentally to
validate the good dynamic performance in generating and regulating dual 125V DC
outputs terminals as telecommunication boards feeders or industrial battery chargers
under various situation including change in the loads and change in the in main
grid voltage amplitude.
KEYWORDS:
1.
Packed U-Cell
2.
PUC5
3.
HPUC
4.
Buck PFC
rectifie
5.
Multilevel converter
6.
Power quality
CONCLUSION:
In
this paper a 5-level rectifier operating in buck mode has been proposed which
is called HPUC as a slight modification to PUC multilevel converter. It has
been demonstrated that the proposed rectifier can deceive the grid by
generating maximum voltage level of 250V at AC side as boost mode while
splitting this voltage value at its two output terminals to provide buck mode
of operation with 125V DC useable for battery chargers or telecommunication
boards’ feeder. Although it has more active switches than other buck rectifier topologies
and some limitations on power balance between loads, overall system works in
boost mode and CCM which results in removing bulky AC and DC filters that
usually used in conventional buck PFC rectifiers. Moreover, generating multilevel
waveform leads to reduced harmonic component of the voltage waveform and
consequently the line current. It also aims at operating with low switching
frequency and small line inductor that all in all characterizes low power
losses and high efficiency of the HPUC rectifier. Comprehensive theoretical studies
and simulations have been performed on power balancing issue of the HPUC
rectifier. Full experimental results in steady state and during load and supply
variation have been illustrated to prove the fact that HPUC topology can be a
good candidate in a new family of buck bridgeless PFC rectifiers with
acceptable performance. Future works can be devoted to developing robust and
nonlinear controllers on the proposed rectifier topology.
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[2]
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[3]
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