Abstract

This paper presents an implementation of an ad-vanced system that uses virtual instrumentation as the main component in the process of measurement and testing of three phase asynchronous motors. This approach permits the replacement of the old analog measurement techniques – which are still in use in the industry applications at some electrical motor testing benches, with the new advanced measurement system bench. This system bench is capable of data acquisition, storage on different media, visualization of relevant graphs, printing or distribution of technical reports or analysis on-line or off-line in an automated manner. The general architecture of the proposed system is focused on the hardware components (transducers, conditioning, data acquisition, calculator) and software components (driver for the acquisition and manipulation-calculation of data, graphical presentation, other auxiliary programs and the ones to bring all the components together, virtual instru-ments). The proposed system allows the application of methods for determining losses and efficiency from tests. Some of the most important requirements of the interna-tional standards for induction motors testing are used: gen-eral technical verification, determination of the windings resistance in DC, no-load testing and running characteristics testing. This system would be very useful in industry appli-cations in the domains of electrical machines for testing workbenches and design laboratories.

Abstract

This paper treats some aspects of the geometrical design of salient synchronous generator, used in railway traction. It focus on the transformation of given experimen-tal data curves into polynomial based regression model which could be use easier in a Computer Aided Design. The final aim of this work is to summarize many detailed by literature recommendations regarding the fabrication ex-perience and to use these to design a Graphical User Inter-face with which, the user perform a specific task in area of designing a salient synchronous generator. For this paper, the proposed task is to interpolate and to plot the depend-ence between ideal covering factor of the polar step and the real one, based on the curves offered by the literature. Using this representation, the user/the designer could choose the appropriate value of the ideal covering factor of the polar step for its case study in a short time and, also, could send this data to the main program. The added value of this work is to create a tool which could be used easier, in different situations. This tool is completely original and is a part of a collection of graphical user interfaces created by the authors to be used in a computer aided design of a salient pole syn-chronous generator calculation.

Abstract

In this paper it is presented a comprehensive design of a dedicated controller for BLDC motor with maximal electric power around 1000W. That controller is a new product in testing stage and it uses high-end components to provide high performance and more flexibility of the implemented algorithms at a low-level cost. The controller can drive a BLDC motor providing the possibility of rotating in both directions, it creates an electromagnetic brake and kinetic energy recovery system. The controller has equipped a 500W electric scooter, and a 1000W electric motor cart and it proved to be reliable, performance and especially flexible. All software routines make the code very fast portable by parameterizing all the implemented software functions.

Abstract

The paper seeks to improve the force developed by an AC electromagnet at maximum air-gap, using the direct optimization method by zooms, based on numerical experiments performed by finite element method (FEM) in ANSYS software. In a previous work, a 5.68% improvement in the static force characteristic of the same device was achieved and particularly, a 12.63% improvement in the force at maximum air-gap, taking into account three very influential geometrical parameters: the rate of bottom core thickness, rate of ring width and the rate of lateral core thickness. The optimization problem was subject to con-straints of maintaining the overall dimensions of the device. The research continues in this paper with the search for the optimal geometrical configuration to provide a maximum developed force in the “open” position, replacing the pa-rameter rate of ring width, having the least influence, with the parameter rate of winding thickness and adding the constraint of maintaining the cross-section of the winding. A device screening ensures that all the new three parameters are worth considering with a confidence level greater than 99%. The solution of the optimization problem brings an improvement of 25.67% of the acting force and of 7.09% of the static characteristic. The magnetic force was determined based on the principle of virtual work, available in ANSYS software.

Abstract

The attention in this paper is directed to the de-sign of a passive damped LCL filter intended to connect the voltage source inverter of an active DC-traction substation to the AC-power supply. Based on the tasks to be fulfilled by the passive connecting filter related to the current filtering and its dynamics, the mathematical foundation of the LCL filter design consists in taking into consideration the trans-fer function of the currents, the switching frequency, the resonance frequency and the compensated harmonics by active filtering. A design algorithms is formulated, by con-sidering the imposition of the attenuation corresponding to the switching frequency. Besides this, the position of the resonance frequency relative to the frequency of the highest order harmonic to be compensated is imposed. The design algorithm is fully formulated, and specific indicators are defined and used to evaluate the performance of the whole active filtering system. The case study taken into considera-tion is of the active DC-traction substation, where the un-controlled traction rectifier is of 12-pulse parallel type. Based on Matlab-Simulink modeling, the simulation of the whole active DC-traction substation operating in both active filtering and regeneration regimes illustrates the proper behavior of the system and the influence of the LCL filter parameters on the power quality performance.

Abstract

This paper makes an analytical study, a numerical and an experimental analysis of the magnetic forces which act in magnetic liquids during the experiment called Quincke’s effect. Quincke’s effect consists in the rise of the magnetic liquid between the poles of an electromagnet. In ferrohydrodynamics theory, the forces acting in the magnetic liquid are not always treated in a uniform manner. The main goal of this paper is to give a consistent macroscopic view, pointing out the importance of the magne-tostriction in the force localization understanding. If the absence of the magnetostrictive term in the forces expres-sion leads to an exclusively superficial localization of the forces, the presence of this term leads both to a superficial localization of forces as well as their presence in the mag-netic liquid volume. Moreover, in the magnetic liquid rise, the volume forces have a significant contribution than the surface forces, so the magnetostrictive term shall not be neglected. In this analysis, the magnetic liquid will be considered as a linear and nonconducting medium placed in a stationary (or quasistationary) field. In order to support the analytical study, a numerical analysis of the magnetic forces and some qualitative experiments were made. The value of the magnetic field forces which act in the magnetic liquid were established in Matlab using the magnetic field strength established by FEM analysis. Analyzing the numerical results and the magnetic liquid deformation obtained by ex-periments, the main conclusion consists in the fact that the magnetostrictive term has an important contribution in the localization of the forces, so it shall be taken into consideration.

Abstract

The paper presents the synthesis of the battery charging system of an electric stand-alone locomotive. The traction converter as boost rectifier is used together with a dedicated control strategy in order to obtain the unity power factor on the grid. Two objectives, often contradic-tory, that can be tracked in the choice of the control mode for the PWM rectifier are highlighted: increasing the per-formance, in order to obtain a rectifier with the best power factor, the best-controlled load current, acceptable switch-ing frequencies for common power transistors, a stable op-eration of the control system, etc.; reducing the complexity and price of the converter by giving up certain elements of the control system, such as the multiplication circuit, the voltage loop, and the use of specialized integrated circuits. A patented structure which responds better to the require-ments and particularities of autonomous vehicles is used. In the control part, direct current control method is adopted and it was implemented by two control loops. The external loop is dedicated to charging current control and the inter-nal loop is dedicated to grid current control. In order to the performance determination, the entire system is analyzed under Simulink environment and the energetic perform-ances are determined. Also, the influence of switching fre-quency is analyzed.

Abstract

This paper contains a theoretical and experimen-tal study on rotary magnetostrictive motor, performed with the purpose of determining the optimal conditions of opera-tion. The two main types of magnetostrictive motors known from the literature, inchworm respectively resonance pre-sent the advantage of large and accurately controlled devel-oped torques for low speed values. The electromagnetic torque developed by the rotary magnetostrictive motor be-ing proportional to the frequency of the current circulating through its inductor, became the subject of frequency con-trol methods. This fact lead to the idea of controlling the torque by controlling the frequency of the current, with direct implication in the domain of torque-controlled drives. Although the actuator represents the central part of any magnetostrictive device, the entire magnetic circuit configu-ration determines the position of the permanent magnet operating point on the linear portion of the magnetostrictive characteristic. The paper includes two different methods, applied for the permanent magnet operating point alloca-tion. The magnetostrictive torque was determined and ex-pressed as function of time, for the full cycle of the periodi-cal current carried by the actuator’s coil. The cycle of the magnetostrictive torque is identical with the cycle of the periodical current circulating through the coil of the actua-tor. The analytical mathematical model developed and pre-sented in the paper considers both regimes, starting and running, making possible the tracking of the operation point. Furthermore, was possible to determine the moment of separation between the rotor disk and the flexible friction element. Several acquired data, recorded at different values of power supply frequency, demonstrate a good correlation between the theory and experiment.

Abstract

The paper presents a method of calculation of LC parameters of reactive balancing compensators of linear time-invariant (LTI) loads supplied with a nonsinusoidal and asymmetrical voltage. The method is based on the Cur-rents’ Physical Components (CPC) – based power theory. Complete compensation of the reactive and unbalanced cur-rents in the presence of the supply voltage harmonics can require compensators of very high complexity. The paper presents a method of calculation of LC parameters of reac-tive balancing compensators with a reduced complexity. The method is illustrated with a numerical example.

CPC-Based Reactive Compensation of Linear Loads Supplied with Asymmetrical
Nonsinusoidal Voltage – Leszek S. Czarnecki

The Rotary Magnetostrictive Motor: a Promising Solution for Low Power Actuators – Alexandru Dalea, Mircea Ignat, Sorin Deleanu, Mihai Iordache, Neculai Galan

Synthesis of the Battery Charging System of a Stand-Alone Electric Locomotive – Alexandru Bitoleanu, Mihaela Popescu, Vlad Constantin Suru, Mihail Rădulescu

How to Design a Passive Damped LCL Coupling Filter for an Active DC-Traction Substation – Mihaela Popescu, Alexandru Bitoleanu, Mircea Dobriceanu, Florin Alexandru Teodorescu

Analytical Study, Numerical Modelling and Experimental Results of the Forces which Act in the Magnetic Liquid Placed between the Poles of an Electromagnet – Daniela Vesa

Application of Direct Optimization Method by Zooms to Improve the Performances of AC Electromagnet – Alin-Iulian Dolan

Controller for BLDC Motors – Florin Ravigan, Laurenţiu Alboteanu, Marius Dumitriu, Ionuţ Zglimbea

An Improved Numerical Model of Heat Transfer Coefficient Corresponding to a Through Connector – Constantin Florin Ocoleanu, Ioan C. Popa

Automatic Sorting and Handling Station Actuated by Pneumatic Drive – Laurenţiu Alboteanu, Gheorghe Manolea, Florin Ravigan

The Resistive Tubular Heater – Mathematical and Simulation Model – Mitică Iustinian Neacă

Simulation of Idle Running Operating Characteristics for Low-Power
Asynchronous Motors – Raluca-Cristina (Presură) Nicolae

Disturbance Analysis for Power Systems Based on LabVIEW Real-Time and Reconfigurable FPGA Modules Using Wavelet Transform – Marcel Nicola, Claudiu-Ionel Nicola, Sebastian Popescu, Dumitru Sacerdoţianu, Marian Duţă

Single/Three-Phase Transformer with Variable Frequency for Electric Locomotives – Berzan Vladimir, Ermurachi Iurie, Ivanov Sergiu

Continuous Monitoring and SCADA Integration of the Sag of Overhead Electricity
Transmission Cables Based on the Measurement of their Slope – Dumitru Sacerdoţianu, Marcel Nicola, Claudiu-Ionel Nicola, Iulian Hurezeanu, Florica Lăzărescu

Implementation of Virtual Instrumentation for Testing of Induction Motors – Gheorghe-Eugen Subţirelu

Analysis of Losses in Brushless Direct Current Motors and Their Influence upon Operation Characteristics – Monica-Adela Enache, Aurel Campeanu, Ion Vlad, Sorin Enache

Current Aspects in the Conception and Performance of Dispatching Manoeuvres
in the National Electric Power Transmission System – Silvia-Maria Digă, Nicolae Digă, Cristian Bratu, Adelaida-Mihaela Duinea

Diagnosis with Analytic Model of a Rectifier for Faults of the Rectifier Control – Virginia Ivanov, Maria Brojboiu, Sergiu Ivanov

Modeling Three-Phase Short-Circuits for Radial Distribution Systems – Horia Bălan, Mircea Ion Buzdugan, Liviu Neamţ

Graphical User Interface to Extrapolate the Ideal Covering Factor of the Polar Step – Gabriela Dana Petropol Şerb , Ion Petropol Şerb

Power line Compromising Emanations Analysis – Vlad Butnaru, Bogdan Trip, Andrei Macovei, Georgiana Roşu, Alexandru Boitan, Simona Halunga

Indirect Current Control Algorithm Implementation and Validation, for Active Filtering Using Constant Switching Frequency Hysteresis Controllers – Mihaita Lincă, Constantin Vlad Suru, Cristina Alexandra Preda

Analysis of the Phaseportrait for the Lü Dynamical System in a Particular Case – Adela Ionescu, Florian Munteanu