Conclusions
This paper has shown that the harmonic attenuation/
amplification effect can be significant for single-phase
power electronic loads. Previous research has recognised
the fact that harmonic amplification can occur, but has not
investigated or analysed the phenomenon under credible
voltage conditions. In this paper, we have proposed
describing the voltage waveshape by using crest indices,
which are used to predict the harmonic current amplification
or reduction. The main findings are
† Whether harmonic amplification or attenuation occurs
depends on the phase angle displacement PD and on the
CF. Higher harmonic currents are more sensitive attenuation
or amplification effects.
† The dependence on PD is clearly stronger than that on CF,
as it could be shown in the results presented in this paper. This
finding greatly expands the development presented in [5],
which attempted to characterise the current distortion by
using CF only.
† The voltage angle displacement PD is caused by the type of
load. In residential areas, where predominantly single-phase
power electronic loads are the dominant non-linear loads,
harmonic attenuation or amplification can be experienced.
But most of the voltage conditions result in harmonic
attenuation, and few cases result in voltage amplification.
† For narrow ranges of voltages (voltages measured in
residential areas), it is possible to predict the individual
harmonic AFh of a diode-bridge single-phase load using the
coupled PDh and CFh. The associated errors are small and
therefore acceptable.
Other indices, such as zero crossing shifting caused by
interharmonics, may also impact the harmonic
amplification/attenuation effect of non-linear loads. This
analysis is currently under research.
Conclusions
This paper has shown that the harmonic attenuation/
amplification effect can be significant for single-phase
power electronic loads. Previous research has recognised
the fact that harmonic amplification can occur, but has not
investigated or analysed the phenomenon under credible
voltage conditions. In this paper, we have proposed
describing the voltage waveshape by using crest indices,
which are used to predict the harmonic current amplification
or reduction. The main findings are
† Whether harmonic amplification or attenuation occurs
depends on the phase angle displacement PD and on the
CF. Higher harmonic currents are more sensitive attenuation
or amplification effects.
† The dependence on PD is clearly stronger than that on CF,
as it could be shown in the results presented in this paper. This
finding greatly expands the development presented in [5],
which attempted to characterise the current distortion by
using CF only.
† The voltage angle displacement PD is caused by the type of
load. In residential areas, where predominantly single-phase
power electronic loads are the dominant non-linear loads,
harmonic attenuation or amplification can be experienced.
But most of the voltage conditions result in harmonic
attenuation, and few cases result in voltage amplification.
† For narrow ranges of voltages (voltages measured in
residential areas), it is possible to predict the individual
harmonic AFh of a diode-bridge single-phase load using the
coupled PDh and CFh. The associated errors are small and
therefore acceptable.
Other indices, such as zero crossing shifting caused by
interharmonics, may also impact the harmonic
amplification/attenuation effect of non-linear loads. This
analysis is currently under research.
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