ABSTRACT:
This paper presents the hardware implementation of a
new control method based on an improved harmonic isolation for active filter
systems. The harmonic generation is based on Self Tuning Filters for the harmonic
isolation and on a modulated hysteresis current controller for the current
control technique. This active filter is intended for harmonic compensation of
a diode rectifier feeding a RL load. The study of the active filter control is
divided in two parts. The first part deals with the harmonic isolator which
generates the harmonic reference currents and is implemented into a Dspace
DS1104 prototyping card. The second part focuses on the generation of the
switching pattern of the IGBTs of the inverter by the modulated hysteresis
current controller, implemented into an analogue card. The use of Self Tuning
Filters instead of classical extraction filters allows extracting directly the voltage
and current fundamental components in the α-β axis at high performances, without any Phase Locked
Loop. The effectiveness of the new proposed method is verified by computer
simulation and validated by experimental study.
SOFTWARE: MATLAB/SIMULINK
BLOCK DIAGRAM:
Fig
1. Power system configuration.
EXPECTED SIMULATION RESULTS:
Fig
2. Simulation results for the phase 1 under sinusoidal voltage conditions: (a)
load current, (b) supply current after compensation
CONCLUSION:
This
paper has discussed the control and performances of a shunt active power
filter. The hardware implementation has been performed based on the optimisation
of the reference current generation and using a modified version of the p-q
theory. The control of the active filter was divided in two parts, the first
one realized by the DSPACE system to generate the reference currents and the
second one achieved by an analogue card for the switching pattern generation,
implementing a modulated hysteresis current controller.
STFs
have been introduced in the proposed modified version of the p-q theory instead
of classical extraction filters (high pass and/or low pass filters) for both
grid voltages and load currents. The use of this filter experimentally leads to
satisfactory performances since it extracts the harmonic currents at high
performances. For the current controller, we implemented the modulated hysteresis
current controller to obtain a fixed switching frequency for the IGBT’s.
The
simulation and the experimental results have demonstrated and conforted the
effectiveness of using STF and modulated hysteresis current controller in the filter
control. In conclusion, the proposed control for shunt active power filter is
effective in installation on an actual power system.
REFERENCES:
[1]
J. C. Das,” Passive filters- Potentialities and limitations” IEEETransactions on
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[2]
H. Akagi, “Active and hybrid filters for power conditioning” IEEE International
Symposium on Indsutrial Electronics, vol 1, (2000).
[3]
P. Jintakosonwit, H. Fujita and H. Akagi,” Control and performance of a
fully-digital-controlled shunt active filter for installation on a power
distribution system” IEEE-Transactions on power electronics, vol. 17, pp.
323-334 (2002).
[4]
M. P. Kazmierkowski and L. Malesani, “Current control techniques for
three-phase voltage source PWM converters: a survey” IEEE Trans. Ind. Elect.
vol.45, n°5, pp. 691-703 (1998).
[5]
H. Akagi, Y. Kanazawa and A. Nabae “Generalized theory of the instantaneous
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