Energy and Power Engineering, 2013, 5, 1115-1119

doi:10.4236/epe.2013.54B213 Published Online July 2013 (http://www.scirp.org/journal/epe)

Active Power Filter Control Using Adaptive Signal

Pr ocessing Techniques

S. A. Temerbaev, V. P. Dovgun, N. P. Bojarskaja, A. F. Sinyagovski

Siberian Federal University, Institute of Space and Information Technologies, Chair of Systems for Automatics,

Computer-Aided Control and Design, Krasnoyarsk, Russia

Email: temwork@mail.ru

Received February, 2013

ABSTRACT

In this paper a new Active Power Filter (APF) control method is proposed . Computation of the load harmonic compen-

sation current is performed by the adaptive notch infinite impulse response (IIR) filter. Performance of the proposed

scheme has been verified by computer simulation. MATLAB/SIMULINK power system toolbox is used to simulate the

proposed system. The simulation results are presented and confirmed the effectiveness of the proposed method.

Keywords: Active Power Filter; Nonlinear Load; Harmonics

1. Introduction

The widespread use of nonlinear devices within the in-

dustrial, commercial and residential sectors has resulted

in substantial reduction of power quality in electric power

systems. Harmonic distortion produced by nonlinear

loads causes several problems, such as increased power

losses in customer equipment, power transformers and

power lines, flicker, shorter life of organic insulation [1].

In recent decades, passive and active harmonic filters

have been recognized as the most effective solutions for

harmonic mitigation.

The passive harmonic filters (PHF), consisting from

capacitors, inductors and resistors have been trad itionally

used for this task [1, 3]. The main advantages of PHF are

design simplicity and low cost. Th ey don’t require a reg-

ular service and can correct the power factor. But PHF

have many disadvantages, such as fixed compensation

characteristics, large size and resonance problems.

In recent years, active power filters (APF) have been

widely investigated for the compensation of harmonic

currents. APF allow to compensating the harmonics and

unbalance, together with power factor correction. Mod-

ern active harmonic filters have superior filtering char-

acteristics, smaller in physical size, more flexible in ap-

plication compared to their passive counterparts. They

are widely used in industrial, commercial, utility net-

works and in electric traction systems [1, 2].

Calculation of compensating signals is the important

part of APF control and affects their transient as well as

steady-state performance. Different control methods have

been proposed, ranging from the use of fast Fourier

transform (FFT) to the instantaneous P-Q theory, artifi-

cial neural networks and adaptive notch filters.

In this paper, an efficient method to obtain compen-

sating signals for the active harmonic filter is considered.

The load harmonic compensation is performed by using

the lattice-form adaptive notch IIR filter. Simulation re-

sults confirm the effectiveness of the proposed method.

2. Shunt Active Power Filter

The active power filters are basically classified into two

types: the shunt type and the series type. One of the most

popular active power filters is the shun t APF. It’s advan-

tages are good current con trol capability, easy p rotection,

and high reliability over series filters. The single-phase

operation scheme of a shunt active filter is shown in

Figure 1.

For each harmonic of order h the nonlinear load is

presented by the equivalent Norton circuit, which con-

sists of the current source

h

with in-parallel imped-

ance

h

. The grid is presented by the Thevenin equiv-

alent, which consists of the voltage source with

series impedance G

U

G

.

The shunt active power filter compensates current

harmonics by injecting equal but opposite harmonic

compensating current, so that the compensated current is

Figure 1. Operation scheme of shunt active filter.

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