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Adaptive recursive inverse-based control
algorithm for shunt active power filter
Abstract:
A new adaptive control technique is proposed for a three-phase shunt active power
filter (SAPF) in this study. The proposed control algorithm is based on recursive
inverse theory which is used here to extract weighted values corresponding to
fundamental active and reactive power components of load currents. This adaptive
control algorithm possesses advantages over other control algorithms in terms of
its reduced computational complexity, fast weight convergence and robust
performance in distorted environment. The SAPF is used to mitigate current
related power quality problems such as harmonics, reactive power and load
unbalancing in both modes of power factor correction and voltage regulation. The
performance of proposed control algorithm of SAPF is demonstrated through
simulation results in Matlab/Simulink environment, which are validated with test
results obtained on the developed experimental prototype of SAPF in the
laboratory.
Existing system:
 The performance of SAPF in load compensation depends on the type of
control algorithm used for extraction of reference currents. Various time
domain control algorithms are reported in the literature. Some conventional
control algorithms are based on instantaneous active–reactive (p–q) power
theory, which perform better under undistorted balanced voltages,
synchronous reference frame theory, power balance theory and improved
hysteresis current control of three-level inverter.
 Other time domain control algorithms are Icosf theory which is designed
using analogue controller, simple peak detection-base technique, one cycle
control which has robust performance, provides simple and improved
harmonic suppression, composite observer based, double deadbeat-loop
control method and improved direct power control strategy.
Proposed system:
 In this paper, a recursive inverse (RI)-based control algorithm is proposed
for three-phase SAPF. This algorithm is robust under distorted environment,
with considerable reduction in computational complexity and achieves faster
convergence than RLS algorithm.
 The weighted values of fundamental active and reactive power components
of load currents are extracted and reference supply currents are generated
using this algorithm.
 The proposed algorithm is used for harmonics elimination, reactive power
compensation and load balancing in power factor correction (PFC) and
voltage regulation modes along with regulation of self-sustained dc bus
voltage.
 The implementation of this algorithm is simple and is based on some
mathematical operations such as multiplication, division and addition, for
error calculation and weight updation.
Circuit diagram:
Advantages:
This adaptive control algorithm possesses advantages over other control algorithms
in terms of its reduced computational complexity, fast weight convergence and
robust performance in distorted environment.
Reference:
1 Singh, B., Chandra, A., Al-Haddad, K.: ‘Power quality: problems and mitigation
techniques’ (John Wiley and Sons, UK, 2015)
2 Ghosh, A., Ledwich, G.: ‘Power quality enhancement using custom power
devices’
(Springer International Edition, Delhi, 2009)
3 Akagi, H., Watanabe, E.H., Aredes, M.: ‘Instantaneous power theory and
applications to power conditioning’ (John Wiley and Sons, New Jersey, 2007)
4 Singh, B., Al-Haddad, K., Chandra, A.: ‘A review of active filters for power
quality
improvement’, IEEE Trans. Ind. Electron., 1999, 46, (5), pp. 960–971