ABSTRACT:
In this paper,
we investigate the effect of unbalanced and distorted supply voltages on the
performance of active power filters that are based on the well-known p-q and
d-q control methods. Our analysis shows that the harmonic suppression performance
of the p-q and d-q control methods deteriorates when non-ideal
sources are used. We propose the use of a self tuning filter (STF) with
the p-q theory or d-q method as a way of alleviating the
detrimental effects of non-ideal supply voltages. Simulation results show that
the proposed method can improve the performance of active power filters under
non-ideal voltage conditions.
SOFTWARE:
MATLAB/SIMULINK
Fig.1.Block diagram of simulated APF
EXPECTED SIMULATION RESULTS:
Fig.2 Three phase balanced
and undistorted (ideal) source voltage
Fig.3. Supply currents with p-q
method under case 1. (THDi=2.1%)
Fig.4. Supply currents with d-q method
under case 1. (THDi=2.07)
Fig.5. Distorted and unbalanced source voltages
for case 2.
Fig.6. Supply currents with p-q method
under case 2.
Fig.7. Supply currents with d-q method
under case 2.
Fig.8. Supply currents with STF based p-q
method under case 3.
Fig.9. Supply currents with STF based d-q
method under case 3.
CONCLUSION:
In this paper, we consider the effect of
an unbalanced and distorted supply on the performance of the well-known p-q theory
and d-q methods for active power filters. The ability of these methods
to combat current harmonics deteriorates significantly when a non-ideal supply
voltage is used. A modification to the p-q and d-q methods is
then proposed for alleviating the effects of an imperfect supply. This involves
the use of a self-tuning filter (STF) with p-q theory and the d-q
method. We show that the total harmonic distortion of source current (THDi)
can be reduced by up to around 2.30 % with the use of a STF under
non-ideal voltage conditions. In addition, our comparative results show that an
STFbased d-q method performs better than an STF-based p-q
theory.
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