EPE Journal Volume 05-1 
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EPE Journal Volume 05-1 - Editorial
EPE Journal Volume 05-1 - Papers



 EPE Journal Volume 05-1 - Editorial 

Fantasy  [Details]
By B. Sneyers

The Editorial of the EPE Journal Volume 05 N1, "Fantasy", written by Ir. Brigitte Sneyers, the Secretary General of EPE Association.


 EPE Journal Volume 05-1 - Papers 

On-Line Monitoring of the Chip Temperature in IGBT Inverters for Propulsion Systems  [Details]
By M. Fasching

A robust and reliable on-line determination of the chip temperature of high power semiconductors is presented. Based on a thermal model and a temperature measurement of the heat sink the chip temperature can be estimated if the semiconductor's losses are known. An easy method is introduced for identifying the parameters of the thermal model. The model shows good consistency with measurements on a 550 kVA IGBT inverter in both , steady state and thermal transients in the range of several milliseconds.

The Next Generation Motor Control Method: Direct Torque Control (DTC)  [Details]
By P. Tiitinen; P. Pohjalainen; J. Lalu

Direct Torque Control (DTC) is the latest AC motor control method developed by ABB. In Direct Torque Control all switch changes are based directly on the electromagnetic state of the motor. Optimum switching is determined for every control cycle on a timelevel of 25 microseconds. That is also the main difference between Direct Torque Control and the traditional AC drive control methods. In DTC, there is no seperate voltage- and frequency controlled PWM modulator. The switch positions of the power module are determined by a calculated stator flux and motor torque. The used selection of the switches forces the stator flux in the direction where the reference values of the torque and the stator flux are achieved. The calculation of the stator flux is based on an accurate motor model and the measurement of the motor input voltage and current. The measurement of the shaft speed is not needed. The reference value of the torque controller either comes from speed controller or is an external reference. The torque reference is modified internally in order to keep the dc intermediate voltage limited and the motor torqie and the inverter current in the allowed range. Direct Torque Control offers excellent dynamic performance, with torque step rise timetypically better than 2 ms. Accurate torque control can also be provided at low frequencies, including zero speed. DTC is realized by using Digital Signal Processors and ASIC technology.

High Performance ASIC Circuit for a Three-Phase Controlled Bridge Fed Static or Dynamic Load  [Details]
By A. S. Zein El Din; J. F. Aubry

The increasing availability of single chip low cost Integrated Circuits has made it possible to reconsider conventional hardware designs for a variety of gating cuircuits. This paper presents a high performance Application Specific Integrated Circuit ASIC's for a three-phase controlled bridge. The dynamic performance of the proposed ASIC is similar to an analog circuit implementation. The resolution of the firing angle is better than 0.043 degrees at 50 Hz. The good dynamic performance was verified by a operating six pulse bridge with the designed ASIC circuit and different firing angles. The bridge was supplying d-c voltage to R-L load or D-C motor. The test result (input a-c phase currents, d-c load current and d-c load voltage) confirm the excellent dynamic performance.

A Technique for Modelling Inverter-Fed Induction Motor Drive Systems  [Details]
By G. B. Giannakopoulos; N. A. Vovos

This paper presents a method for formulating the dynamic model of inverter-fed induction motor drive systems. An efficient model for the machine, which eliminates the time-varying terms of the inductance matrix, is used. This model has the additional advantage that can be directly interfaced with the inverter switching circuit, which is simulated in a flexible way using the state space approach. To demonstrate the efficiency of the proposed formulation, a voltage source inverter-fed induction motor drive is simulated and some transient response results are given.

Static Frequency Converter with Double-Branch Inverter for Supplying Three-Phase Asynchronous Motors  [Details]
By D. Alexa

In this paper, the diagram is presented for a static frequency converter with two-phase PWM inverter. The operating principle of the PWM inverter with high fundamental content output voltage is described.

Influence of the Driver Circuits in the Generation and Transmission of EMI in a Power Converter, Effects on its Electromagnetic Susceptibility  [Details]
By F. Costa; E. Laboure; A. Puzo; A. Pons

This paper presents EMC problems relative to the driver circuits of power converters. Driver circuits may create conducted and radiated interferences, but also may be disturbed by the power part of the converter, involving failures in the driver and converter distruction. Different insulated drivers circuit technologies (optic couplers, pulse transformers) are compared relatively to their vulnerability and their capability to transmit conducted parasitic currents or to radiate parasitic fields. Solutions will be proposed to minimize parasitic interferences transmitted or created in the driver circuit, to improve the converter safety and reduce the emission levels.