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 EPE 1997 – 32: Dialogue Session DS3e: MODELLING AND SIMULATION, USER APPLICATION EXPERIENCES 
 You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1997 - Conference > EPE 1997 – 32: Dialogue Session DS3e: MODELLING AND SIMULATION, USER APPLICATION EXPERIENCES 
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   MODELING OF POWER CONVERTERS USING PARALLELED INTELLIGENT IGBT POWER MODULES 
 By P. Hofer-Nose; N. Karrer 
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Abstract: Despite an enormous amount of publications on power semiconductor modeling, circuit simulation packages (Saber, Pspice e.g.) still lack of accurate power semiconductor models. Available models need a large number of parameters; but not all of them, like doping profile, active area, can easily be extracted through measurements. It is shown that current sharing and power losses between paralleled semiconductor devices can be analyzed using piecewise linear models. The method presented is highly accurate with an error of less than five percents. The necessary parameters for these models can be extracted through measurements. Following this approach, the behavior of a power electronic systems including paralleled chips, IGBT/diode modules or intelligent power modules (IPM) can be efficiently predicted.

 
   LEVITATION SYSTEM FOR MELTING WITH CLASS E INVERTER 
 By B. Grzesik; W. Burlikowski; J. Junak; Z. Kaczmarczyk 
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Abstract: A levitation system (lMHz, 400W) designed for melting samples of small dimensions is presented. It is based on the Class E inverter. The system was examined by means of theoretical analysis, finite element method simulation (ANSYS®) and experiments. There are energy relations concerning the levitation system dealt with in the paper, e.g. the influence of the coil pipe cross-section on the power distribution in the system.

 
   900 kW TWO-QUADRANT SWITCHED MODE POWER SUPPLY WITH LARGE BANDWIDTH AND EXTREMELY LOW RIPPLE FOR SYNCHROTRON PARTICLE ACCELERATION CONSISTING OF IGBT's AND ... 
 By L.A.E. van Lieshout; A.J.J. Colijn 
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Abstract: In the field of synchrotron particle acceleration two-quadrant power supplies are used for the purpose of ramped current generation. The inductive load magnet(s) require large voltage variations to produce a precisely controlled current with trapezium waveform. The switched mode power supply is a new and simplified concept in comparision with the application of a thyristor converter including passive and active filtering sofar. Input reactive power consumption is almost nil, the mains transformer rating can be reduced largely. The current controller contains two PI-controllers to make the following error zero during the ramps. One of the PI-controllers has the feature of auto adaptation to compensate for load saturation up to - 70 %. From 18-bit DAC input to actual current the following error is less than 4 microS. The load current ripple is almost negligible ( <2 ppm). Serious attention is paid to derating of IGBT's for this pulsed load cycle application.

 
   ELECTRICAL SUPPLY SUITABLE FOR DIRECT RESISTANCE FLUID HEATING INSTALLATIONS 
 By P. Mauras; D. Pratmarty; N. Fintescu 
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Abstract: Electrical supply of direct resistance heating installations is difficult to design because of the major change in load characteristics. A specific 15 kW supply prototype has been developed, with the additional constraint of not producing disturbances in the supply system. The chosen structure comprises three conversion levels, the control system of the third level being specially designed to guarantee the absence of a d.c. component in the 0utput wave (in order to forestall clectro-chemical phenomena).

 
   ON THE DESIGN OF A HIGH FREQUENCY HIGH POWER FOUR QUADRANT POWER CONVERTER FOR SUPERCONDUCTING MAGNETS 
 By E. J.·Dede; J. A. Carrasco; J. M. Benavent; F. Bordry; A. Dupaquier; A. Ferreres 
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Abstract: The paper describes the implementation of a four quadrant (±1500 A, ±15 V) power converter to feed a superconducting magnet for particle accelerator applications. The use of high frequency soft switching techniques permits mass and volume reduction. Coordination of the different converter subsystems is achieved through three domain control.

 
   POWER SUPPLY FOR A FAST FIELD CYCLING NMR SPECTROMETER USING IGBTs OPERATING IN THE ACTIVE ZONE 
 By D. M. Sousa; E. Rommel; J. Santana; J. Fernando Silva; P. J. Sebastiano; A.C. Ribeiro 
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Abstract: We describe an accurate current source for fast field cycling Nuclear Magnetic Resonance (NMR), employing paralleled IGBTs operating in the active zone. We present and discuss aspects of the implementation of paralleled IGBTs working in the active zone, the design of the controllers needed to obtain response times in the ms range, together with simulation and experimental results.

 
   A SWITCHING POWER AMPLIFIER FOR ACTIVE MAGNETIC SUSPENSIONS 
 By S. Carabelli; A. Crivelli; A. Iannantuoni; R. Ippoliti; F. Maddaleno; M. Muzzarelli 
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Abstract: The design of a switching power amplifier is tailored for the characteristic impedance represented by the driving coil windings of an active magnetic suspension. A full bridge amplifier with two active switches and two diodes is implemented to obtain a unidirectional output current and bipolar output voltage. In order to decrease the electrical noise, the bridge is driven to obtain a three level output voltage. A double edge PWM modulation with triangular wave, a common mode and a differential mode filters are used to reduce the output frequency contents. System has been tested on a rotor suspended in a complete industrial magnetic suspension.

 
   ADVANCED DIGITAL CONTROL SCHEME OF A PARALLELED BRIDGE TYPE CURRENT TRACKING HIGH POWER CONVERSION AMPLIFIER FOR MAGNETIC RESONANCE IMAGING 
 By S. Watanabe; P. Boyagoda; M. Nakaoka; H. Takano 
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Abstract: This paper presents a Two-paralleled Bridge Power Conversion Circuit using switch-mode power current tracking technique in order to generate a gradient magnetic field in the Magnetic Resonance Imaging (MRI) system. This power amplifier is connected in parallel with the conventional 4-switch type full-bridge PWM power conversion circuit using IGBTs at their inputs/outputs in order to realize further high-power density. A digital control scheme for PWM power conversion circuit requires minimized the current ripple and improved rise/fall response characteristics of the current in the Gradient Coils (GCs). It is proposed in this paper that A unique scheme can achieve the objective. This power amplifier can be easily used in the advanced MRI because the output current waves are not restricted to ramped-square waves and can assume any arbitrary waveform. It is proved that the proposed technique will highly enlarge the diagnostic target and improve the image quality of MRI.

 
   PHASE LOCKING CONTROL OF A RESONANT DC-AC CONVERTER 
 By J.-M. Hube; D. Flieller; J.-P. Louis; X. Quan 
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Abstract: This paper presents a new command strategy for a serial DC-AC converter for induction heating based on the phase locking of the current frequency with an external clock. The duty cycle of the clock is used to control the peak to peak current value with a classical P.l. controller. A small signal sampled-data model is set up to study the stability of the control loop and some experimental results are also shown in this paper.

 
   MODELLING OF POWER ELECTRONICS CIRCUITS ASSOCIATED WITH NON-LINEAR MAGNETIC DEVICES 
 By J.F. Charpentier; Y. Lefevre; H. Piquet 
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Abstract: In this paper a method for modelling power electronics circuits associated with nonlinear electromagnetic devices is proposed. This method is based on the simultaneous resolution of the circuit equations and the field equations in electromagnetic devices. The equations are automatically determined. The field equations are established using a 2D finite element method. The. circuit equations· are determined in state form. A general solution for taking into account the switching of semiconductors is proposed. This method allows to consider local saturation of the ferromagnetic materials in the electromagnetic devices associated with static converters. Examples are presented to validate and illustrate the proposed method.

 
   DEVELOPMENT OF AN INTELLIGENT FLUORESCENT LAMP BALLAST BASED ON NEURON CHIP 
 By J. M. Alonso; J. Ribas; A. J. Calleja; E. Lopez; M. Rico 
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Abstract: A new intelligent ballast implemented around a Neuron Chip control circuit is presented in this paper. Power factor correction (PFC) and resonant inverter (RI) stages are used to supply tlle lamps. Switching frequency is controlled directly from the Neuron Chip I/O port, allowing to implement soft-igniting and dimming. strategies. Communications through the power line are also included using a special power line transceiver. The ballast constitutes a complete intelligent node able to operate in Local Operating Networks (LON).

 
   SINUSOIDAL VOLTAGE WITH DIRECT FOLLOW-UP CONTROL IN VOLTAGE SOURCE MODIFIED TOPOLOGY INVERTER 
 By W. Koczara; A. Niedzialkowski 
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Abstract: This paper describes a sinusoidal voltage direct follow-up control method of voltage source inverter. The inverter is considered as a sinusoidal voltage source for the applications with constant voltage and constant or variable frequency. However the inverter is supplied from DC voltage bus, its main structure - four transistor bridge, is switching the DC current. This is realised by combining the buck inverter with the current source full bridge inverter. The modified structure of system allows control voltage across output capacitor directly by switching responding transistors. The appropriate signals are produced in the microprocessor control block by comparison ofreference signal and feedback signal. The accuracy of generated voltage depends on width of hysteresis band and is limited by maximum value of transistor switching frequency. In paper is described simple two-band follow-up control method. The equivalent circuits analysis, used for setting logical function of switching, allows build more advanced structures of control with combining of inductance current signal. The simulation results are verified by an experimental 2kVA inverter.