EPE Journal Volume 08-3/4 
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EPE Journal Volume 08-3/4 - Editorial
EPE Journal Volume 08-3/4 - Papers



 EPE Journal Volume 08-3/4 - Editorial 

EPE-PEMC 2000 Kosice: The Right Step to Unification of European Power Electronics World  [Details]
By V. Fédak

The Editorial of the EPE Journal Volume 08 N°3/4, "EPE-PEMC 2000 Kosice: The Right Step to Unification of European Power Electronics World", written by Prof. Viliam Fedák, the Chairman of EPE-PEMC 2000.


 EPE Journal Volume 08-3/4 - Papers 

Study on dV/dt Susceptibility of a MCT under Low Control Voltage  [Details]
By S. Roubertou; R. Ehlinger; J. P. Chante

As a thyristor, the MCT (MOS Controlled Thyristor) is not sensitive to dV/dt if the base emitter junction of one of its inner transistor is shorted. However for the MCT, this requires sufficiant gate control voltage. This condition is not satisfied in some power switching applications (e.g. static relay) when power and control circuits are simultaniously switched on.

This paper presents and analyses the dV/dt susceptibility of a PMCT, with a capability of 75 A - 600 V, under low control signal and with temperature influence.

PWM Soft-Single-Switched Converters  [Details]
By M. S. Vilela; J. B. Vieira Jr.; J. A. Lambert; L. C. de Freitas; V. J. Farias

This paper presents serveral converters which, having only a single active switch, are able to operate with PWM characteristics in a soft switching way. In addition such converters can work in high switching frequencies for wide load range without great limitations.
In order to illustrate the operating principles of these converters a detailed analysis, including simulations and experimental tests are carried out. The validity of these converters is assured by the obtained results.

A Novel Uninterruptible Power Supply System with Sinusoidal Input-Output Characteristics and Simplified Control Circuit  [Details]
By G. Ioannidis; E. Xanthoulis; S.N. Manias

In this paper a novel UPS topology is presented and analysed. The proposed UPS consists of three power stages. The first stage is a SMR which utilises a buck-boost converter for active power correction, the second stage is a high frequency inverter that provides ohmic isolation and voltage matching and last, the third stage is a low frequency SPWM inverter. Moreover, the proposed UPS exhibits sinusoidal input/output characteristics, high power density and simple control circuit.

Synchronous Machine Parameters Estimation using Stochastic Method  [Details]
By M. L. Zhu; M. Crappe; M. Renglet; B. Mpanda-Mabwe

The paper describes an original time-domain method for the identification of Synchronous Machine (SM) parameters using on-line tests. The method combines Kalman Filter (KF) to estimate the state of the system and Maximum Likelyhood (ML) method for parameter estimation. The proposed on-line measurement based approach to generator modelling has the advantage of the direct measurement of actual transient behaviors of synchronous machine under system operating conditions. This algorithm is able to identify the parameters of SM using the data measured during any transient period. It is robust to the noise in the process and measurements. The emphasise the sensitivity of the estimated parameters to load conditions, various tests are performed on a micro machine rated (2 kVA, 220 V, 1500 rpm). It is shown that the different sets of parameters obtained are coherent.

Use of PWM-Inverter to Determine Parameters for Saturated Induction Machines with Current Displacement Rotor  [Details]
By O. V. Thorsen; M. Dalva

The intention of this work is to introduce a new method for measuring the induction motor parameters by the help of a standard PWM-frequency converter, and to compare the results with those from a variable frequency test with sinusoidal voltage and also with a variable speed test. The purpose of measuring parameters of a deep bar motor is to design suitable equivalent circuits and mathematical models that take skin effect and saturation into account. Only in particular cases the T-parameter's variation with frequency and current are given by the manufacturer, in most cases the customer has to find a method to determine them.

The method is discussed on the base of the motor's equivalent circuit for harmonic voltage components when a non-sinusoidal voltage is impressed, and losses, saturation and skin effect are taken into account. The variable frequency test with inverter supply has been performed on different motors and by inverters of different design. Measurements in the laboratory show good agreement between inverter supply tests and variable speed- and sinusoidal voltage tests. The rotor impedance calculated from inverter tests is practically the same as for the sinusoidal voltage or variable speed test, provided the fundamental values of voltages, currents and powers are used in the calculations.

Comparison of Different Motor Types for Electric Vehicle Application  [Details]
By JR. Hadji-Minaglou; G. Henneberger

The drive of an electric vehicle requires a small volume, a high power to weight ratio, a high efficiency, a wide speed range, reliability and low costs in manufacturing and maintenance. In this article is presented the comparison of induction motors (ASM's), permanent magnet synchronous motors (PMSM's) and a permanent magnet synchronous motor with auxiliary exciting windings (HYB).
Because of absence of maintenance and its large robustness the squirrel-cage ASM is absolutely suitable to equip an electric vehicle. To reach a wide speed range (over 7000 rpm) and a high efficiency the motor must be designed with low stray reactance's and coppercage rotor. This does not lead to a weight optimal solution.
The PMSM with high energy rare earth magnets has a higher efficiency than the ASM, because it does not need a magnitizing current, which produces additional losses. It also can reach speeds as high as the ASM, by feeding the stator windings with an additional negative winding current. But such properties are only possible with a small number of pole pairs.
The HYB has a high number of pole pairs, that is more intersting from the weight point of view, but it needs auxiliary exciting windings. By field-strengthening at low speed the motor can deliver a high torque if necessary. By field-weakening in the rotor and feeding the stator with a negative direct current the motor can also reach the maximal speed. Prototypes of each synchronous machine have been designed by FEM-analysis, built and measured on a test bench in the institute.

The Energy Factor in Induction Heating Systems  [Details]
By J. R. García; A. Martínez; J. M. Burdío

This work gives answer to an important question usually asked in induction heating designs: given a coil and a workpiece, which are the optimum parameters (frequency and coil-workpiece geometry) to heat this system?
To answer this question a new parameter called Energy Factor (EF) is defined in electromagnetic and in circuit terms. This factor indicates the transfer energy efficiency between two systems, in the case of an induction heating system, between the coil and the load.