Nauki Techniczne

Archives of Electrical Engineering

Zawartość

Archives of Electrical Engineering | 2012 | vol. 61 | No 4 December |

Abstrakt

In this paper, an analysis of the induction motor control scheme based on the Direct Rotor Flux Oriented Control (DRFOC) for a whole speed range, including fieldweakening (FW) regions is presented. Two field-weakening algorithms have been compared and verified through simulation with a 3.0 [kW] induction motor drive.

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Autorzy i Afiliacje

K. Nguyen-Thac
T. Orlowska-Kowalska
G. Tarchala

Abstrakt

Some physical concepts important for a hysteresis model (effective field, anhysteretic magnetization) are discussed on the example of Jiles-Atherton model. The Jiles-Atherton model reveals some drawbacks, which make this model more difficult to be applied in electrical engineering. In particular, it does not describe accurately the magnetization curves after a reversal, moreover complex magnetization cycles are poorly represented. On the other hand, the phenomenological description proposed by Takács seems to be a valuable alternative to the Jiles-Atherton formalism. The concept of effective field may be easily incorporated in the description.

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Autorzy i Afiliacje

Krzysztof Chwastek

Abstrakt

The calculation results of the static field parameters for permanent magnet linear synchronous motor have been presented in this work. The influence of the construction temperature on the parameters has been analyzed mathematically. Models for magnetic and temperature fields determination have been formulated. Two kinds of permanent magnets (NdFeB and SmCo) have been considered. The distribution of the thermal field has been obtained using the finite element method (FEM).

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Autorzy i Afiliacje

Andrzej Waindok

Abstrakt

A study on plug-in electric vehicle (PEV) charging load and its impacts on distribution transformers loss-of-life, is presented in this paper. The assessment is based on residential PEV battery charging. As the exact forecasting of the charging load is not possible, the method for predicting the electric vehicle (EV) charging load is stochastically formulated. With the help of the stochastic model, the effect of fixed, time of use, and real-time charging rates on the charging load and the resultant impact on transformer derating is investigated. A 38-bus test system is adopted as the test system including industrial harmonic sources. Test results demonstrate that uncontrolled EV charging might causes a noticeable change in the K-factor of the transformer, emerging the need for derating, while applying real-time rates for battery charging loads conquers this problem even in case of harmonic-rich chargers.

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Autorzy i Afiliacje

Hessamoddin Jouybari-Moghaddam

Abstrakt

This paper presents a simplified modeling, simulation and Experimental analysis of permanent magnet brushless dc motors (PMBLDC) for sensorless operation. This model provides a mechanism for monitoring and controlling of voltage, current, Speer and torque. The sensorless scheme employs direct back emf based zero crossing detection for controlling the dynamic characteristics.

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Autorzy i Afiliacje

E. Kaliappan
C. Chellamuthu

Abstrakt

This paper presents a new strategy for optimal placement of multi-type FACTS devices with a view to minimize losses besides enhancing the voltage profile using biogeography based optimization. The strategy places three types of FACTS devices that include static VAR compensator, thyristor controlled series compensator and unified power flow controller; and offers optimal locations for placement, type and parameters of the FACTS devices. Test results on IEEE 14, 30 and 57 bus systems reveal the superiority of the algorithm.

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Autorzy i Afiliacje

A. Subramanian
G. Ravi

Abstrakt

The paper presents a method for estimation of converter drive parameters. This estimation encompassed three types of drives, i.e. a static Scherbius drive, a driver with a brushless direct current (BLDC) motor and a drive with a voltage inverter. For drive modelling and parameter estimation, the author implemented original program mes written in FORTRAN. As well as these, the paper describes an objective function applied for the estimation. The author also compares gradient and gradientless methods, chich are applied for minimization of the objective function. Finally, the author explains the estimation results for example drives, focusing on the coincidence of theoretical and empirical waveforms. The abovementioned procedure led to the general rule, which facilitates estimation efficiency.

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Autorzy i Afiliacje

Ryszard Beniak

Abstrakt

This paper presents optimization results for a two-phase, modular transverse flux switched reluctance motor (TFSRM) with an outer rotor. In particular, the main disadvantage of the considered motor structure, that is the zero starting torque in some rotor positions, is eliminated by construction optimization. A numerical model of the motor developed in the Flux3D program is coupled with a Matlab-based evolutionary algorithm for optimization of construction parameters of the magnetic circuit. The elaboratem algorithm is also connected with a database to limit the computation costs. Three objective functions are taken into account for the motor integral parameter improvement. The fundamental role of a type of an optimization criterion function is comparatively analyzed and a new effective criterion function is introduced.

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Autorzy i Afiliacje

Marian Łukaniszyn
Marcin Kowol
Janusz Kołodziej

Abstrakt

Permanent magnet motors are more and more frequently used in various applications. In this group motors with a trapezoidal EMF deserve a special attention. They are characterized by a simple construction, high efficiency and high torque overload. A certain drawback of BLDC motors are difficulties with an operation at a speed above the nominal value. The article presents the results of investigations into the variablestructure electronic commutator designed for the drive of a small electric vehicle equipped with BLDC motors. Such a solution allows extending the standard range of the drive's speed. The considerations contained in the article focus on the possibilities and effects of regeneration mode in the proposed topology of converter. A theoretical analysis has been presented as well as computer simulations carried out by means of Matlab- Simulink, which were then verified at a laboratory. The tests were finished with trias conducted using a small electric vehicle Elipsa.

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Autorzy i Afiliacje

Tomasz Biskup

Abstrakt

A numerical method is developed for estimation of temperature distributions inside tissues heated by external RF hyperthermia with external circular coil. The computational method relies on a solution of electromagnetic field problem in sinusoidal steadyt state. The heat transfer problem is treated in three dimensions with axis symmetry model. Than the bioheat diffusion equation under a steady-state condition is solved to determine the temperature distributions inside tumour and surrounding tissues. The heat removal due to the blood circulation is also taken into account. Numerical results are presented for heat generated by ferromagnetic nanoparticles in order to minimize negative effects of radiofrequency radiation.

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Autorzy i Afiliacje

Eugeniusz Kurgan

Abstrakt

The averaged models of switch-mode DC-DC power converters are discussed. Two methods of averaged model derivation are considered - the first, based on statespace averaging and the second, on the switch averaging approach. The simplest converters: BUCK, BOOST and BUCK-BOOST working in CCM (continuous conduction mode) or DCM are taken as examples in detailed considerations. Apart from the ideal converters, the more realistic case of converters with parasitic resistances is analyzed. The switch averaging approach is used more frequently than the other and is believed to be more convenient in practical applications. It is shown however, that in the deriving the averaged models based on the switch-averaging approach, some informalities have been made, which may be the source of errors in the case of converters with parasitic resistances, or working in DCM mode.

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Autorzy i Afiliacje

Włodzimierz Janke

Abstrakt

The separation of variables approach to formulate the averaged models of DC-DC switch-mode power converters is presented in the paper. The proposed method is applied to basic converters such as BUCK, BOOST and BUCK-BOOST. The ideal converters or converters with parasitic resistances, working in CCM and in DCM mode are considered. The models are presented in the form of equation systems for large signal, steady-state and small-signal case. It is shown, that the models obtained by separation of variables approach differ in some situations from standard models based on switch averaging method.

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Autorzy i Afiliacje

Włodzimierz Janke

Instrukcja dla autorów

ARCHIVES OF ELECTRICAL ENGINEERING (AEE) (previously Archiwum Elektrotechniki), quarterly journal of the Polish Academy of Sciences is OpenAccess, publishing original scientific articles and short communiques from all branches of Electrical Power Engineering exclusively in English. The main fields of interest are related to the theory & engineering of the components of an electrical power system: switching devices, arresters, reactors, conductors, etc. together with basic questions of their insulation, ampacity, switching capability etc.; electrical machines and transformers; modelling & calculation of circuits; electrical & magnetic fields problems; electromagnetic compatibility; control problems; power electronics; electrical power engineering; nondestructive testing & nondestructive evaluation.

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