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