Marian Pasko

Sizing of active power filters using some optimization strategies

Purpose – The change in the way of active power filters (APF) location can lead to overall cost reduction due to less number or less power of APFs required. The goal of this paper was to minimize the APF currents what is equivalent to solution with less apparent power of installed devices. The next step consists in development of new methods of APF optimal location.Design/methodology/approach – Some scripts integrating optimization and harmonic analysis methods in Matlab and PCFLO software environments have been developed in order to achieve the goal.Findings – Solution to the minimization problem determines the current spectrum of an APF connected to a selected system bus in accordance with some optimization strategies which among others enable minimization of THDV coefficients.Research limitations/implications – The APF control algorithm defined in the frequency domain and based on given current spectrum could lead to some problems with synchronization between APF instantaneous current and compensated c...

Performance and accuracy comparison of fixed and floating-point realizations of the Active Power Filter control algorithm

The comparison of performance and accuracy of the active power filter control algorithm realizations has been presented in the paper. The worked out algorithms are based on dq synchronous frame control strategy. The following Texas Instruments digital signal controllers were used for the realization: fixed-point TMS320F2812 and floating-point TMS320F28335. The TMS320F28335 digital signal controller is the first floating-point controller in the C2000 family. It combines flexible control-specific interfaces and ease of use of an industrial microcontroller(MCU) with the processing power of DSP technology (up to 300 MFLOPS). Using of the floating-point digital signal processor allows improving accuracy of the computation, particularly in digital filtering (IIR low-pass filter) which has a direct influence on the quality of the generated current waveforms. The worked out algorithms have been practically verified on APF prototype which was built in the Institute of Industrial Electrical Engineering and Computer Science. The presented problems have been illustrated by laboratory results.

Hybrid power filter with single tuned passive filter - dynamical properties

The paper has been intended to present the analysis of hybrid power filter (HPF) dynamical properties. The hybrid power filter with single tuned passive filter has been taken into consideration. The present paper deals with influence of control algorithm and its components on dynamical properties of HPF. Experimental results of transient states have also been included in the article.

Compensation based on active power filters - The cost minimization

The paper deals with the problem of power quality and its solution. Passive or active compensators are usually used to reduce distortions of voltage and current waveforms. Active power filters seem to be the best choice if the effect of compensation is the only criterion. However, the financial cost of such a solution put the potential investors off. The paper shows that the cost could be reduced considerably if the optimization of active power filter allocation, as well as their nominal currents, is carried out. Two cases have been considered - active power filters with a classical control algorithm, which operates locally and aims at obtaining sinusoidal shape of waveforms in the point of installation, and active power filters with a modified control algorithm, which aims at reduction of waveform distortions in all nodes of an analyzed power system. Goal functions and optimization problems for both cases have been defined.

Genetic and Combinatorial Algorithms for Optimal Sizing and Placement of Active Power Filters

Abstract The paper deals with cost effective compensator placement and sizing. It becomes one of the most important problems in contemporary electrical networks, in which voltage and current waveform distortions increase year-by-year reaching or even exceeding limit values. The suppression of distortions could be carried out by means of three types of compensators, i.e., passive filters, active power filters and hybrid filters. So far, passive filters have been more popular mainly because of economic reasons, but active and hybrid filters have some advantages which should cause their wider application in the near future. Active power filter placement and sizing could be regarded as an optimization problem. A few objective functions have been proposed for this problem. In this paper we compare solutions obtained by means of combinatorial and genetic approaches. The theoretical discussion is followed by examples of active power filter placement and sizing

Principles of Electrical Power Control

This chapter contains a review of the scientific works published till date in the field of power theory for systems with periodic non-sinusoidal waveforms. Nowadays, electrical energy belongs to goods indispensable in everyday life. Dynamic increase in the number of installed nonlinear loads, that are the source of higher harmonics in current and voltage waveforms, results in deterioration of electrical energy parameters. Higher harmonics make the electrical energy quality much worse. The number of power theories and papers concerning these issues give evidence about the importance of the problems of working condition optimisation in power systems.

Symmetrization of asymmetrical nonlinear three‐phase load supplied from non‐ideal sinusoidal voltage source

Purpose – The purpose of this paper is to deal with the problem of symmetrization of asymmetrical three‐phase delta connected nonlinear load. In the model of the three‐phase sinusoidal voltage source have also been included inner impedances. The purpose is to obtain symmetrical line currents of the voltage source, to minimize RMS values of currents and to minimize higher harmonics generated by nonlinear loads.Design/methodology/approach – This symmetrization of the system is realized by means of a symmetrizing system, which is composed of LC one‐ports. In order to solve the problem the symmetrical component theory is applied. The structure of symmetrizing system is consisted of two components: parameters determined for the basic harmonic and the filter for elimination of the higher harmonics generated by nonlinear loads.Findings – After symmetrization line currents of the source will be symmetrical with lower RMS values than before symmetrization, and the source will generate the greater active power than...

Symmetrization of asymmetrical three‐phase load supplied from non‐ideal periodic non‐sinusoidal voltage source using simplified structure of the compensator

Purpose – The problems presented in the paper concern a three‐phase four‐wire system with periodical non‐sinusoidal voltage sources with inner impedances and asymmetrical linear three‐phase loads. Generally, the line currents of the system are asymmetrical. The purpose of the paper is to improve the working conditions of the system by means of symmetrization.Design/methodology/approach – A method of symmetrization of these systems has been proposed. In this paper, the symmetrization problem has been solved by using the symmetrical components theory and compensation of reactive power for each of voltage harmonics under consideration.Findings – After symmetrization currents become symmetrical and their RMS values and active power on source impedances become lower. The realization of symmetrization makes possible: reduction of RMS values of source currents, an assurance of equal loads for individual phases of the system supplied from sources with inner impedances, after symmetrization the voltage source gene...

A method for optimization of the working point of the N‐phase (N+1)‐wire systems with nonlinear loads

Purpose – The paper proposes to deal with the problems concerning the N‐phase (N+1)‐wire system with sinusoidal voltage sources and nonlinear loads. In the model of the N‐phase voltage source the inner impedance has been included. The problem of the optimization of working conditions of the system is a minimization of RMS value of its line currents as well as their distortions caused by nonlinear loads.Design/methodology/approach – The solution of this problem is based on the frequency domain. It is obtained by means of Lagranges multipliers and the suitable measurement experiment.Findings – After optimization source currents are sinusoidal with minimized RMS values. After connection of the designed compensator to the system under research the phase currents are equal to determined active currents.Research limitations/implications – This method can be used for some classes of nonlinear loads, i.e. for systems with inertialess (non‐reactive) elements, which consume the active power of the basic harmonic o...

Time-invariant and time-varying filters versus neural approach applied to DC component estimation in control algorithms of active power filters

Abstract This paper presents an application of digital filters and neural networks to the extraction of a DC signal component. This problem arises, among others, in control of active power filters (APF) used for power quality improvement. Solutions to the basic problem of DC component estimation are well-known and so the difficulty of the task comes rather from the required minimization of the calculation time. It should ensure fast reaction of the control system to load changes. As a result, lower value of the current total harmonic distortion coefficient (THD) and better efficiency of the APF can be obtained. The paper includes propositions of both time-varying and neural filters as well as comparison with the classical approach to the DC component estimation based on infinite impulse response (IIR) low-pass filters. The results obtained by simulations have been presented. The future work will be devoted to digital signal processor implementation of APF control algorithms based on the best solution.