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EPE Journal Volume 03-3 - Papers
EPE Journal Volume 03-3 - Editorial
By B. Sneyers; G. Maggetto
The Editorial of the EPE Journal Volume 3 N°3, "EPE Journal: how about 1994?", written by Ir. Brigitte Sneyers, Editor and Prof. Gaston Maggetto, Past-President of EPE Association.
EPE Journal Volume 03-3 - Papers
By D. O'Sullivan
In order to undestand the key differences between space and industrial power electronics, it is essential that those features that are unique to the space environment are clearly identified. In the first part of this paper those key drivers that effect the choice of design approach will be described and the remainder of the paper will illustrate how these drivers effect the choice of regulator topologiesand the overall approach to power system design.
The first part of this paper can be found in EPE Journal Volume 1993-2 and the third part in EPE Journal Volume 1993-4.
By J. B. Klaassens; M. P. N. van Wesenbeeck; P. Bauer
This paper presents a survey of research and development on resonant converter topologies for DC and AC applications. The presentation is primarily focused on the methods for soft-switching DC and AC power converters operating with high switching frequency. By switching at the zero-crossings of the voltage over or the current through the semiconductor switch, the dynamic losses can be reduced permitting higher switching frequencies. The motivation for miniaturization of power converters has been the driving force for the application of higher and higher internal operation frequencies. The trend to develop power converters with improved characteristics is based on an increased of the switching frequency. Since the switching frequency is high, waveforms at the in- and output terminals of the converter are now easily synthesized with lower distortion. The resonant converter topologies are already state-of-the-art for DC-DC conversion applications. Presently research is conducted especially on the application of methods of soft-switching in AC converters. These converters have the potential to play a significant role in the future generation of power converters for AC motor drives and UPS systems.
By P. Zwanziger
The economic and technical advantages power converters with IGBTs offer are the result of lower costs for gate drive circuitry, a favourable trend in price developments and the enhanced ruggedness of these semiconductor devices. Different applications can be implemented by simply adapting the gate drive circuit, though specific switching characteristics and parasitic stray inductances have to be taken into account, especially under fault conditions. The example of a safe operating area (SOA) from the view of application is calculated to illustrate this. Turn-off under short-circuit conditions in the critical time space of a gate drive circuit will become manageable by active clamping of the collector over-voltage. Parallel connections can be quatitatively described by dynamic and steady-state temperature-dependent asymmetries in the current distribution. An analysis of the electrothermal correlations between the elements creates a better calculation basis for investigating the sensitivity of parameters to different temperature coefficients of the IGBT and freewheeling diode. This is finally folowed by a presentation from the user's point of view of problems to be expected later with regard to increasing the switching capacity of IGBT modules.
Part II of this paper can be read in EPE Journal Volume 1993-4.
By J.-M. Charreton
Power in conventional light dimmer circuits is controlled by TRIACS. They require a serial inductor for EMI filtering and a fuse to protect them against overload and short circuit.
This paper describes a soft dimmer based on the use of an IGBT as a turn-off controllable switch. This allows to control the current switching slope, cancelling by the way, the serial inductor and its associated acoustical noise.
By S. M. Sharaf; M. I. Mahmoud
This paper presents the theoretical design and practical application of a modified controller to a DC motor for reference speed tracking control of DC drives. In the proposed technique, the motor performance can be controlled for input and external disturbances such as required speed trajectory tracking and load torque changes, respectively. A feedforward controller is used to achieve motor speed tracking for the reference speed changes. An optimal feedback controller is used to eliminate the speed effect due to the load torque changes. An additional feedback control loop of the motor load torque is developed to ensure the intensity fast speed stabilization even at large load disturbances. The effectiveness of the proposed control scheme is demonstrated by using a laboratory drive system with an on-line IBM PC computer and interfacing modules. Test results presented in this paper prove that the proposed control strategy is very effective in high performance input speed tracking applications and intensive load disturbances.