| EPE 2001 - Topic 10d: Active Filters and Harmonics |
| You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2001 - Conference > EPE 2001 - Topic 10: POWER ELECTRONICS IN GENERATION, TRANSMISSION AND DISTRIBUTION OF ELECTRICAL ENERGY > EPE 2001 - Topic 10d: Active Filters and Harmonics |
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 | A control sheme for an APF implemented with a PWM-NPC-VSI
By R. Domke; L. Morán; J. Espinoza; J. Dixon | [View]
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Abstract: A simple control scheme for an active power filter implemented with a three-level NPC voltage-source inverter is presented and analyzed in this paper. The proposed scheme compensates simultaneously displacement power factor and current harmonics. The advantages of using a three-level VSI are based in improving the compensation characteristics and reaching a higher voltage level. The control scheme is discussed in terms of priciples of operations under steady state and transient conditions. The proposed control scheme presents a new technique to generate the required current reference signals and to keep the inverter dc voltage constant. Simulated results prove the viability of the proposed scheme, which are validated by experimental results.
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| | A New Combined Control Method for Four-Wire Shunt Active Filters
By A. Abellán; J. M. Benavent; E. Figueres; I. Miró | [View]
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Abstract: Nowadays, four-wire shunt active power filters are used to compensate current harmonics, reactive
power and unbalanced currents. To control these, it is necessary to obtain active filter reference
currents starting from load currents. There are various ways to obtain these reference currents [1]-[5].
In this work a UPF-SFR control method [8] for a four-wire shunt active filter is presented. Depending
on the position occupied by a three channel analogical switch, this method allows two different ways
of operating. In the first, the set formed by the non-linear load and the filter behaves like a resistor
(UPF, unity power factor). In the second the line currents are perfectly sinusoidal (SRF, synchronous
reference frame). The voltage THD according to [7] will impose the change between both ways of
operating. The filter currents are controlled by a space vector current controller [9] based on three
level hysteresis comparators using Scott’s transformation. The system has been simulated for both
unbalanced and non-sinusoidal load currents and AC voltages showing waveforms of the line currents
in both ways of operating. The non-linear load is composed of three single-phase diode-bridge
rectifiers with both a resistance and a filter capacitor each one.
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| | A New Concept Of Power Active Filtering For Ac Traction Power Supply
By B. Dobrucky; V. Racek; P. Cabaj; M. Roch; R. Kucera | [View]
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Abstract: The paper deals with new concept of power active filter for AC traction power supply. The new idea
of that is using of one power active filter (PAF) in half-bridge connection (HB-PAF) for each supplied
traction section. Moreover, further half-bridge PAF can be used as redundant one. So, the PAF comprises
m-phase filtering unit with higher reliability due to redundancy. It is also possible to separate
fundamental- and high harmonic components for filtering. The analysis of half bridge PAF as well as
control method proposal are given in the paper.
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| | A Parallel Power Conditioning System with Energy Storage Capability...
By D. Casadei; G. Grandi; C. Rossi | [View]
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Abstract: Power Conditioning System (PCS) with energy storage capability is proposed as a viable
solution for improving the power quality in industrial plants. Several tasks, such as reactive
power compensation, current harmonic reduction, and smoothing of pulsating loads can be
performed at the same time. In this paper the principle of operation of the PCS will be
described, and the analysis will be focused on the control of the energy flow among the system
components. Numerical simulations and experimental tests will be shown to demonstrate the
effectiveness of the PCS to reduce flicker phenomena and to compensate harmonic current
components and reactive power. With minor changes of the hardware structure and of the
control algorithms the PCS can also be operated as Uninterruptible Power Supply (UPS).
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| | Active filtering of supply voltage with series-connected VSC
By J. Svensson; A. Sannino | [View]
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Abstract: In this paper, a static series compensator for voltage sag mitigation is completed with a voltage
active filtering function for further power quality improvement. The control system developed here
performs isolation of voltage harmonics in several rotating coordinate systems, thus being able to
cancel (or reduce) only selected harmonics, if desired. Moreover, it compensates for the effect of the
converter output filter, which is frequency-dependent. Simulated results confirm the capability of the
device to cancel symmetrical and unsymmetrical harmonics. Moreover, it is shown by using actual
voltage sag recordings that the addition of the active filtering feature does not affect the speed of
response during transients.
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| | Advancd Corrector with FPGA-Based PLL to Improve Performance
By M.A.E Alali; Y.A. Chapuis; L. Zhou; F.Braun; S. Saadate | [View]
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Abstract: This paper deals with the series active conditioner which aims to compensate all voltage disturbances
able to occur in an electrical network. A series active filter with a second order output passive filter
for ripple frequency attenuation is studied in the goal of the compensation of harmonic and/or
unbalanced voltage, and voltage sag. The advantages of the use of a PLL in the voltage disturbances
identification is discussed. An improved RST corrector (RSTadv) is proposed to regulate the injected
voltage solving the phase shift problem. The robustness of this corrector is verified especially in the
case of voltage sag compensation. Other regulation methods (RST, PID) are highlighted through
simulations performed by SABER numerical code.
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| | An Adaptive Controller for D-Statcom in the Stationary Reference Frame
By G. Escobar; A.M. Stankovic; P. Mattavelli | [View]
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Abstract: The paper presents a passivity–based controller for Distribution Static synchronous Compensator (D–Statcom)
aimed to compensate reactive power and unbalanced harmonics in the general case of distorted and unbalanced
source voltages and load currents. The proposed approach is based on the measurements of line
currents, and ensures precise compensation for selected harmonics. Moreover, in order to compensate for
the unavoidable uncertainty in certain system parameters, adaptation is added to the passivity–based controller.
One of the major advantages of the proposed solution compared to conventional alternatives is that
we are able to perform precise tracking (including higher order harmonics) even in the presence of a relatively
low switching frequency, i.e., in presence of an inverter with limited bandwidth. Simulation and
experimental results are provided to illustrate the merits of our solution.
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| | An Improved Unified Power Quality Conditioner
By P. Singh; J.M.Pacas; C.M.Bhatia | [View]
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Abstract: In this paper, a new power circuit configuration of a 3- phase unified power quality conditioner having
low power rated active filters and a simplified algorithm for the calculation of the reference signals is
proposed. It has the capability to compensate the distortions and the unbalances of current and voltage
waveforms. The effectiveness of the proposed power quality conditioner has been demonstrated by
means of experimental results.
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| | Analisis of DC link capacitor volt. balan. in multilevel active filter
By R. Strzelecki; G. Benysek; J. Rusiñski; E. Kot | [View]
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Abstract: This paper presents results of simulation of a three-phase parallel active power filter implemented
with: -three and five level diode clamped (DC) inverter; -isolated series h-bridge (ISHB) three and five
level inverter. There will be clarified effect of voltage unbalance on active power filter's source
element, and discussed how to avoid this problem. In the paper there will be presented behavior of the
active power filters (APF), implemented with counted upper inverters, in case of sudden changes of
the load. We will also discuss influence of different voltage balancing algorithms on APF behavior.
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| | Compensation of Current Harmonics in DFIM Systems
By A. Dittrich | [View]
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Abstract: Power quality is becoming an issue of increasing importance for wind and water power plants. In the
paper the subject of mains current harmonic reduction is discussed with special emphasis to doublyfed
generator systems. Several approaches for compensation are investigated theoretically and by
measurements.
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| | Control Implementation of a Three-phase Load Comp. Active Conditioner
By J. Prieto; P. Salmerón; J. R. Vázquez | [View]
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Abstract: A design method for the control implementation of a combined series-shunt active power filter (Load
Compensation Active Conditioner, LCAC) for electrical power quality improvement is proposed. This
active conditioner allows to cancel source voltage harmonics, to symmetrize the supply voltage, and to
eliminate current harmonics and reactive/unbalanced load currents. Practical case results are presented
to support the performance of the new control design.
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| | Control Of 3 Phase Parallel Compensators With Non-Sinusoidal Supply
By R. Blasco-Giménez; R.S. Pena; R. Cardenas | [View]
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Abstract: Abstract: This paper studies the shortcomings of standard control techniques for parallel
compensators and proposes a control strategy for harmonic current cancellation, load balancing and
reactive power compensation with unbalanced and distorted supply. The proposed controllers provide
full decoupling of dc link voltage and ac current control in highly distorted supplies and can be
designed using standard linear control tools. The final version of the paper will include experimental
results on a 22kW converter.
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| | DC bus balance of a three level inverter used as active filter
By J. Balcells; M. Lamich; D. Gonzáles | [View]
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Abstract: Preliminary tests of a single phase active filter, based on a three level VSI, with split up DC bus are
presented. The converter is controlled as a current source by three level threshold comparators. A separate
control of positive and negative threshold levels allows the balance of the two DC bus halves. A closed
loop controller was proposed and tested. Different values for gain and average constants have been tried.
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| | Design and control of a CLD
By Å. Ekström; P. Bennich; M. De Oliveira; A. Wikström | [View]
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Abstract: With the increasing demands on the power quality as experienced by sensitive customers, the interest
for so called Custom Power devices has increased significantly during recent years. This contribution
presents the design and control of a pure semiconductor based Current Limiting Device (CLD), which
can be controlled not only to limit but also actively control fault currents in order to reduce the
influence of faults in distribution networks.
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| | Fast Line Conditioners using New PWM AC Chopper Topology
By E. Lefeuvre; T. Meynard; P. Viarouge | [View]
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Abstract: Three-phase series line conditioners are proposed, using a new PWM AC chopper structure associated
with transformers. They compensate efficiently voltage drops, harmonic distortion and voltage
unbalance. Their topology and modes of operation are presented herein.
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| | Fuzzy Active Filter Performance in Transient Conditions
By A. Dell’Aquila; A. Lecci; P. Zanchetta; M. Liserre | [View]
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Abstract: The paper presents a fuzzy logic based shunt active filter both as regard the PWM inverter current
control and the capacitor energy management. Focus is addressed on reference computing with the
instantaneous powers theory improved by the introduction of a regulation factor which is inferenced
by a fuzzy controller. Moreover a fuzzy control acts on the inverter switches duty cycles ensuring an
optimum current tracking. The aim of this regulation is to face sudden changes of load power demand
during transients. To test the effectiveness of the proposed control, the active filter is applied to
compensate the distorted currents produced by a diode-rectifier front-end-type PWM-VSI induction
motor drive working in transient conditions. The simulation results highlight a very high reduction of
the line current harmonic distortion with an acceptable switching frequency and the good results
obtained, thanks to the fuzzy logic based control, even in transient conditions.
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| | H-Inf. Control For Power Quality Conditioner
By J. Dzieza; Z. Hanzelka | [View]
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Abstract: A new approach to an active power conditioner (APC) control system based on H-inf technique is presented. The H-inf controller should preserves good performances independently of the load, network and APC
characteristics. Both performance and robustness objectives are expressed in terms of constraints in the H-inf
norm of some weighted closed-loop transfer functions.
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| | Integrated Power Quality Compensator Based on Sliding Mode Controller
By B-R. Lin; S-C. Tsay; M-S. Liao | [View]
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Abstract: Recently active power filter is an important way to increase the power quality due to the widely use of
nonlinear loads and switching mode power converters. This paper presents a simple control strategy
which employed the switching mode rectifier to work simultaneously as a power factor corrector and
an active power filter to decrease current harmonics drawn from the nonlinear load. Since no
additional active power filter is needed, the cost of this configuration is lower than that of the
conventional active power filter configuration. The sliding mode controller is used in the current
control loop to achieve fast dynamics. Only the source currents are measured in the proposed control
scheme to reduce the elements of current sensors needed in the conventional control approach. A
simple proportional-integral controller is adopted in the voltage control loop to achieve slow dynamics.
The proposed scheme can achieve high power factor, current harmonic elimination and no dedicated
active power filter. A diode rectifier fed capacitive load as the nonlinear load is taken on AC mains to
demonstrate the effectiveness of the proposed active rectifier for reactive power and current harmonics
compensation.
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| | Neural Networks Application to control an Active Power Filter
By J. R. Vázquez, P. R. Salmerón; F. J. Alcántara | [View]
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Abstract: In this paper, a new method to control an active power filter using Neural Networks is presented.
Currently, there is an increase of voltage and current harmonics in power systems, caused by nonlinear
loads. The Active Power Filters (APFs) are used to compensate the generated harmonics and to
correct the load power factor. The proposed control design is a Pulse Width Modulation (PWM)
control with two blocks that include Neural Networks. Adaptive networks estimate the reference
compensation currents. On the other hand, a multilayer feedforward network (trained by a
backpropagation algorithm) that works as hysteresis band comparator is used. A practical case with
Matlab-Simulink is presented to check the proposed control performance.
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| | New Control Algorithm for Shunt Active Filters, based on STVF.
By M. A. Perales; J. L. Mora; J. M. Carrasco; L. García Franquelo | [View]
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Abstract: A new, improved, method for calculating the reference of a shunt active filter is presented. This
method lays on a filter, which is able to extract the main component of a vector signal. This filter acts
as a Phase-Locked Loop, capturing a particular frequency. The output of this filter is in phase with the
frequency isolated, and has its amplitude. Simulation and experimental results confirms the validity of
the proposed algorithm.
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| | Novel Instantaneous Power Compensation Theory in Three-Phase Systems
By H. Kim; F. Blaabjerg; B. Bak-Jensen; J. Choi | [View]
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Abstract: This paper proposes a novel power compensation theory in three-phase systems. Three
transformation methods were compared to explain the theory more clearly. Proposed power compensation
theory provides two-degree of freedom to control the system currents by only compensating the instantaneous
imaginary powers without using any energy storage element. This paper proposes a Reference Current
Control method that controls the neutral-line current and the rotating phase currents separately and makes
the system currents sinusoidal and balanced in any circuit conditions such as unbalanced or distorted
voltages and/or unbalanced or nonlinear loads. Simulation results show the superiority of the power
compensation theory both in definition and compensation.
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| | Power System Impedance Measurement In The Presence Of Non-Linear Loads
By B. Palethorpe; M. Sumner; D. Thomas | [View]
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Abstract: This paper examines a technique for on-line measurement of power system supply impedance. The
method employs a power electronic inverter to apply a short duration transient onto the energised
power network. The voltage disturbance and the consequent current transient are measured and may
be used to identify supply impedance. Experimental results demonstrate the effectiveness of the
technique for identification of the impedance of transmission lines and linear loads. The performance
of this method is also examined in the presence of non-linear loads. An alternative data processing
method is introduced in order to improve the technique and to compensate for the measurement
problems associated with non-linear loads. This is also verified experimentally.
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| | Single-phase active filter for high-order harmonics compensation
By K-B. Lee; M-H. Woo; J-H. Song; I. Choy | [View]
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Abstract: A single-phase active power filter for high-order harmonic current compensation is presented in
this paper. In modern railway locomotives, multi-paralleled PWM converters provide unity power
factor operation with low THD, but their high-order harmonics current may provoke interference
problems to the railway tack signal and public telecommunication lines. A hybrid digital filter is
proposed to extract the harmonics reference currents compensated in active filters. A prediction
algorithm to compensate the delay problem that appears in the deadbeat current control is also
proposed to produce a predicted harmonics reference current. The effectiveness of the proposed
algorithms are verified through simulations and experiments.
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| | sliding mode control of parallel hybrid filters
By S. Tnani; J. Bosche; J-P. Gaubert; G. Champenois | [View]
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Abstract: In this paper, the authors propose a novel control strategy of active hybrid filters. Sliding
mode control is introduced to allow active filtering of load harmonics and active damping of passive
filter connected in parallel with the active filter. When connected in power grid, the complete system is
adjusted to prevent the risk of resonance as well as harmonic filtering. A complete modelling of the
system is achieved and robustness of the control law is analysed. Complete simulation of the system
validates efficiency of the control law.
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| | System Design of Three Phase Active Filters using Time Domain techniqu
By S. Ponnaluri; A. Brickwedde | [View]
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Abstract: A new way for designing and analyzing the Active Filters based on voltage source converters is
presented. A systematic step by step design procedure is explained covering almost entire electrical
system design of Active Filter. This method not only enables a completely new design of a system but
can also be used to analyze an existing system to find its suitability for a given load. As the proposed
technique is based on time domain it can be implemented online in the control processor to analyze &
monitor various. For example the junction temperature of the devices can be calculated online to
decide the current limits of converter thereby making it possible to operate the converter at its
maximum capability at all times. Even though voltage source converters are considered in this paper,
it can be equally applied to current source inverter based systems. MATLAB was used for developing
the design program. This offline program executes in less than a second on a Pentium Computer. The
program takes basic parameters like load current waveform, supply voltage waveform, percentage
ripple current & voltage etc as inputs and produces the specifications of various components as output.
An online implementation has been done on the Active Filter Controller and the additional
computational time required was only a small fraction of the control code of the Active Filter. Being
generalized in nature the approach can be used for designing other systems like UPS.
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| | Unified Definition of Powers in Single-Phase and Three-Phase Systems
By H. Kim; F. Blaabjerg; B. Bak-Jensen | [View]
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Abstract: This paper proposes a unified definition of powers for various circuit conditions such as
balanced/unbalanced, sinusoidal/non-sinusoidal, and linear/nonlinear, for single-phase systems and threephase
systems. Conventional reactive power is more classified into an interactive power and a scattering
power. These powers are defined both in the time domain and the frequency domain consistently, and agree
well with the conservation law. Several important power quality factors are defined to measure and evaluate
the power quality for the various circuits in the single-phase and three-phase systems. Simulation results show the power quality factors can evaluate and classify the various circuit conditions explicitly.
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| | Unified Power Quality Conditioner Based On Current Source Converter To
By D. Graovac; V. Kati; A. Rufer; J. Kne evi | [View]
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Abstract: Nonlinear devices, such as power electronics converters, inject harmonic currents in the AC system
and increase overall reactive power demanded by the equivalent load. Also, the number of sensitive
loads that require ideal sinusoidal supply voltages for their proper operation has increased. In order to
keep power quality under limits proposed by standards, it is necessary to include some sort of
compensation. Different types of power quality compensators of higher or lower complexity have been
reported. The aim of this paper is to present a unified power quality conditioner (UPQC) that consists
of two three-phase current-source converters connected on the same inductive DC link. Such system
has faster phase voltage control loop than its voltage-source converter based counterpart, as well as the
inherent short circuit protection capability. Also, in this case passive filter connection between UPQC
and the load is not needed, which minimizes the cost of the system.
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| | Vector Operated Three-phase Active-Power-Filter with One-Cycle Control
By C. Qiao; T. Jin; K. M. Smedley | [View]
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Abstract: THIS PAPER WAS WITHDRAWN FROM THE EPE 2001 CONFERENCE !!!
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