EPE Association: EPE 1991 - 19 - Session 2.8: HIGH POWER DEVICES AND PASSIVE COMPONENTS

EPE 1991 - 19 - Session 2.8: HIGH POWER DEVICES AND PASSIVE COMPONENTS
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1991 - Conference > EPE 1991 - 19 - Session 2.8: HIGH POWER DEVICES AND PASSIVE COMPONENTS

   [return to parent folder]

   AIR-CORE VS. IRON-CORE INDUCTORS FOR POWER ELECTRONICS APPLICATIONS
By A. Kusko; S. Peeran [View]
[Download]

Abstract: Designs are compared for air-core and iron-core inductors for power-electronic equipment in harmonic filters, dc link chokes, smoothing reactors, and other applications. Considerable information is available in the literature for small and large inductors, but not for intermediate sizes. The two types of inductors, of the same relative size, are compared over a dimensional and frequency range. Guidance and references are provided for the designer of power-electronic equipment .

   NON-LINEAR CURRENT TRANSFORMER FOR ACCURATE MEASUREMENT OF G.T.O. THYR!STOR TURN-OFF CHARACTERISTICS
By F. J. Wakeman [View]
[Download]

Abstract: The use of Gate Turn-off Thyristors in ever higher frequency applications increases the importance of the turn-off energy and minimum off-time. The accurate measurement of both parameters is dependent upon the ability to resolve the turn-off tail current to near extinction. A non-linear current transformer has been developed which allows for the accurate measurement of tail current. When used in conjunction with an 8 bit digital storage oscilloscope the unit allows for the tail current to be measured at a lower range of amperes per volt than the rest of the current wave-form. The greater resolution of current per data point, down to some hundreds of milli-amperes for >1000A devices, permit accurate measurement of turn-off time and energy to extinction of the tail current. The results obtained with a prototype non-linear current transformer were compared against other measurement methods and found to offer a good, low cost, solution to this difficult measurement.

   TRANSIENT THERMAL RESPONSE OF POWER SEMICONDUCTORS TO SHORT POWER PULSES
By Steve Clemente [View]
[Download]

Abstract: Thermal response curves used to calculate the peak junction temperature of power semiconductors are normally derived by experimental identification of the parameters of a known model. Unfortunately the model, developed many years ago, is inappropriate for large surges of short time duration, as they are encountered in present day power conditioning systems. An alterative model is derived, the limits of its accuracy are estimated, and a correction factor is elaborated. A verification of the accuracy of the two methods is also presented. Physical characteristics of popular MOSFET and IGBT dies are also provided to allow the reader to calculate the rise in junction temperature in specific applications.

   A VERY FAST POWER HYBRID MODULE WORKING IN THYRISTOR MODE
By D. Lafore; J. M. Li; J. Redoutey [View]
[Download]

Abstract: Using conventional fast thyristors in current-fed resonant inverters, maximum frequency is limited to about 10 kHz due to turn-off delay time tq. Increasing the maximum frequency needs composite switches having thyristor function, made by serie connexion of a diode and a high speed controlled device (IGBT, GTO, BJT or MOS). This paper presents a power hybrid module including a cascode switch, its antisaturated driver circuit and a serie connnected diode. Design of the module is presented considering the electrical, thermal and technological problems. Results of a 10 A - 1000V module in current-fed resonant converter working in the range 100 - 300 kHz are shown.

   AN ACCURATE ONE-DIMENSIONAL MODEL FOR THE ANALYSIS OF THE TURN-OFF PERFORMANCE OF ANODE SHORTED GTO THYRISTORS
By Z. Khatir; R. Lallemand [View]
[Download]

Abstract: The switching behavior of Gate Turn Off thyristor with shorted anode emitter has been calculated numerically by solving the semiconductor basic equations in an "equivalent" one-dimensional model device. It is taken into account of all significant physical semiconductor mechanisms and the interaction with a non-ideal external circuit is considered. Computations, using this model, are made on micro-computers and successfully compared with the results of measurements conducted at the INRETS's LTN-laboratory on a number of anode shorted GTO's of different origins. Short circuits between anode emitter and N-base are taken into account by an additional term in the electron recombination rate. lt is shown that the calculated switching behavior for a given device remain accurate when the external circuit is changed. The computational time of a turn-off simulation is approximately 40 minutes with a personal computer such as IBM-PC's or Macimosh Il's. Owing to the results obtained and the accurate description of the tailing current waveforms on a number of GTO's with different circuits of operation, such a simulation model is found to be a valuable tool for circuit design and device selection.

   A Driver Circuit for High Power GTO Devices
By A. Brambilla, E. Dallago [View]
[Download]

Abstract: A driver circuit for GTO-thyristors applied to power converters for railway vehicles is presented. The driver studied and the realized prototype concern power GTOs (about 4500V - 3000A). The driver circuit is made up of a signal part that generates output logical signals on the basis of other input signals and a power part directly connected to the GTO. The power part is realized with DMOS mosfets rather than BJTs to give easier driving and higher commutation speed. The gate behaviour of the GTO and the behaviour of the driver are studied and outlined. Some simulations of the power circuit of the driver were done and the results are discussed and compared with the experimental ones.

   CHARACTERIZATION OF TRANSFORMER CORES USING A NEW MUTUAL IMPEDANCE FORMULA
By W. G. Hurley; P. S. McNamara [View]
[Download]

Abstract: This paper describes a new method for calculating mutual and leakage impedances in transformer windings. The new formula is derived from a solution of Maxwell's Equations for coils on ferromagnetic cores. The frequency dependence of eddy current losses in the core are taken in to account and represented by the resistive component of the impedance formula. The new formula is based on the physical dimensions of the windings and core and also the magnetic permeability and electrical resistivity of the ferromagnetic core. Equivalent resistivities are derived for non-homogeneous laminated and powdered iron cores. It is shown that any core can be characterized by its magnetic permeability and equivalent electrical resistivity. The new methodology overcomes the traditional assumptions of ideal core magnetic material and negligible core losses.

   A CIRCUIT SIMULATION MODEL FOR THE HIGH POWER DIODE
By P. A. Persson [View]
[Download]

Abstract: In this paper a new circuit simulation model for the high power diode is derived, that accurately describes the dynamics of the excess charge in its low doped region. This excess charge is responsible for its dynamic characteristics, and is important in most applications. The model is based on the semiconductor equations in ambipolar form and the model parameters all have physical relevance. The approach is to divide the charge into a number of subregions and describe the distribution in each one with a second degree polynomial. At the boundaries between the subregions, the distribution and its derivative have to be continuous. To each subregion belongs a charge control equation which includes terms for recombination and net supply of charge from the "outside". Other important effects, such as recombination in the emitters and the influence of free holes in the space charge layer on the voltage during reverse recovery are also included.

   GATE DRIVE UNIT FOR 2500 A - 4500 V GTO's
By T. J. I. Lottman [View]
[Download]

Abstract: Gate drive circuits for GTO's have been known for some years. However with increasing power ratings of variable-speed drives for asynchronous motors, power semiconductors capable of carrying high currents and withstanding high voltages are needed. This paper presents a new generation of gate drivers for these large GTO's. Each driver consists of a galvanically independant voltage supply, optical fibres for signal transfer and a supervision circuit. GTO on/off sensing is based on gate-sensing rather then anode-sensing.

   A NEW METHOD TO ELIMINATE THE EFFECTS OF THE HIGH VOLTAGE TRANSFORMER PARASITIC ELEMENTS IN A STATIC RESONANT SUPPLY
By B. Tala-Ighil; X. Tian; D. Matt; C. Glaize [View]
[Download]

Abstract: This paper describes a method to eliminate the effects induced by the high voltage transformer parasitic elements in a static resonant supply. This is done not by modifying the converter structure but by redefining the high voltage transformer structure. For this, a high voltage DC-DC converter has been designed and a model of the high voltage transformer established. The influence of the transformer parasitic elements on the structure operation is validated with the help of simulations and experiments. A method is then proposed to eliminate the effects induced by the high voltage transformer parasitic capacitance. This method has a technical advantage : it is easier to put into operation than to reduce the parasitic capacitance.

   A REGENERATIVE SNUBBER FOR THREE LEVEL HIGH POWER GTO INVERTERS
By In-Dong Kim; Gyu-Hyeong Cho [View]
[Download]

Abstract: A regenerative snubber for three-level high-power GTO inverter having simple construction and high efficiency is proposed. It consists of series inductor and shunt capacitor snubbers with DC/DC converter for energy recovery trapped in the snubbers. In particular, the new DC/DC converter as an essential component of regenerative snubber has very low switching loss due to resonant operation with zero voltage switching and has small size due to high switching frequency over 10 KHz using power transistors. The proposed regenerative snubber is also thought to be applicable for other multi-level high power GTO inverters.

   WOUND COMPONENT PARASITIC ELEMENTS: CALCULATION, SIMULATION AND EXPERIMENTAL VALIDATION IN HIGH FREQUENCY POWER SUPPLY
By E. Laveuve; M. Bensoam; J. P. Karadec [View]
[Download]

Abstract: The aim of this paper is to improve understanding of high frequency behaviour of wound components. Three points are specially studied: magnetic core losses, leakage inductances and stray capacitances. Equivalent circuits are set up and analytjcally justified. Experimental study of several prototypes enables magnetic core influence, winding geometry, etc to be separated. Finally, these equivalent circuits are introduced in a power electronic sirnulation software and the results are compared with the measurements acquired on a real power supply.

   INVESTIGATION ON HIGH-TEMPERATURE OPERATION FOR IGBT COMPONENTS
By Ch. Schaeffer; J. P. Ferrieux; M. L. Locatelli; S. H. Gamal; S. Volut [View]
[Download]

Abstract: The purpose of this paper is to study the thermal transit of IGBT for using it in high power high frequency operations. Firstly the high temperature behaviour of silicon have been analysed above standard limits and the consequences on electrical parameters have been defined. Secondly, the components, which are able to operate in the 600 V - 400 A range, have been studied in order to evaluate losses and maximum switching frequency. Furthermore, experiments have been made on IGBT transistors. Owing to electrical junction temperature measurement, a thermal model has been established and compared with a simulated model.

   TWO-PHASE COOLING EVOLUTION OF HIGH POWER SEMICONDUCTORS
By T. Jomard; U. Eckes; M. Lallemand [View]
[Download]

Abstract: Cooling by nucleate boiling is actually one of the most efficient means to remove heat from a component. For that reason, it has been used widely in the field of cooling of power electronic components. A fluid was of interest due to its various qualities: the trichlorofluoroethane. However, this latter is condemned to a short term by the Montreal protocol and the London conference. Therefore, in order to find a substitute to it, we have to note all constraints acting on the used fluid and then elaborate a schedule of trials allowing the correct grasping of the new characteristics.

   HEAT PIPE COOLING OF ELECTRONIC COMPONENTS
By M. Lebailly [View]
[Download]

Abstract: The high effective thermal conductivity of a heat pipe enables heat to be transferred at high efficiency over considerable distances. For instance, for high power device within a module containing other temperature sensitive components, heat pipe connects the heat sources directly to the heat sink without temperature increasing of the other components. On the other hand, heat pipe could be used for temperature flattening in a electronic system. A heat pipe is a high thermal conductance device in which a liquid is in equilibrium with its vapor. In the evaporation area the device is cooled and in condenser the heat is evacuated to the sink ; the liquid goes from condenser to evaporator by gravity or capillary force. Now for industrial applications, XERAM have developped a large range of heat pipes for high power components cooling : with water of organic fluids as working fluid. The thermal resistance for those devices is as low as 40 to 50° K.Kw-1, and depends of air speed cooling flow and also of total power applied to the evaporator.

   SEMICONDUCTORS AT LOW TEMPERATURE
By J. F. Kärner; H. W. Lorenzen; W. Rehm [View]
[Download]

Abstract: At present, power diodes are operated at 4.2 K in order to protect superconduting accelerator magnets from quenches. A Further uso might be the protection of the single coils or coil sections of superconducting magnetic energy storage (SMES) plants. As the reactive coil voltage at transient operation exceeds the threshold voltage of diodes by far, thyristors will come to be used instead. The contribution presents the results of experimental investigations on a series of thyristors at 77 K; it also reports on preliminary tests carried out at 4.2 K. A short description of the test set-up to be installed at the TU München for extensive measurements at 4.2 K is given.

   BIDIRECTIONAL OPTOELECTRONIC THYRISTORS RATED AT 80 A, 1200 V
By N. A. Tetervova; R. I. Rybak; V. A. Zlobin; Z. I. Kafengauz [View]
[Download]

Abstract: The paper presents results of investigations aimed at designing production prototypes of bidirectional optoelectronic thyristors (optotriacs) rated at a current to 80 A and a repetitive peak voltage to 1,200V. Main geometrical and electrophysical parameters of optotriac structures are calculated, and the interconnection of those with photosensitivity and dynamic characteristics is studied. By using infra-red equipment and a method of scanning electron microscopy specific features of switching processes in a turned-on-by-light, five-layer n-p-n-p-n structure having an amplifying gate are investigated. On the basis of the investigations a design and technological methods of fabricating high-power optotriacs are developed. Optotriac prototypes have been fabricated and tested.

   THE DC-LINK INDUCTOR SINGLE LEG CAPACITOR ENERGY RECOVERING SNUBBER
By Victor Manuel Guzman; Maria Gimenez De Guzman; Peter Bowler [View]
[Download]

Abstract: A snubber configuration having minimum component count and minimum losses is presented for inverters. Component count reduction is achieved by sharing a single snubber capacitor between each pair of power switches in each leg and relocating leg inductances to the dc-link, where they are shared by all inverter legs. This is particulary interesting when using devices in power pack modules. In high load çurrent operation no net energy is transfered to the snubber, giving no losses snubber operation. At low load, excess energy is stored as current in the inductors. A way to return this energy to the supply is presented, thereby achieving minimum losses under all load conditions.

   STUDIES OF REVERSE RECOVERY EFFECTS IN POWER FAST RECOVERY DIODES
By G. Vaher; V. Ruhamkin; M. Tarma [View]
[Download]

Abstract: The possibilities of controlling the minority carrier lifetime of electron and proton irradiation and platinum diffusion are compared. The investigations the reverse recovery parameters in the range of temperature 25°c...180°c with the interval 10°c point to the increasing trr with temperature by abrupt steps. The lowest values of trr (1.3 ... 1.5 us) and Krr (1.1 ... 1.2) are obtained by proton irradiation and one side platinum diffusion as a result of low lifetime value in P+P emitter.

   POWER ELECTRONIC DEVICES AND THEIR APPLICATION TO TRANSMISSION AND INDUSTRY
By G. R. Clark; G. A. Ferry [View]
[Download]

Abstract: The rapid development of power electronic devices has been matched by the utilisation of these devices, in an ever widening variety of applications. This paper describes the essential characteristics of the principal devices, currently available and under development, and their relevance to applications in the field of electrical power engineering. Several such applications - to power transmission, industrial processes and transportation - are discussed in terms of their power electronic device requirements, the benefits gained from advances in device technology and their influence on device development.

   MODELLING OF HIGH POWER THYRISTORS UP TO SURGE LEVELS FOR OBTAINING V-I CHARACTERISTICS
By . Y. A. Shammas; J. K. Chester [View]
[Download]

Abstract: There are situations where a knowledge of the isothermal V-I characteristics of high power thyristors up to high current levels can be very useful. Obtaining such characteristics is immediately made difficult by the time taken for a large device to become fully conducting (the spreading time) and the need to prevent it from heating up. If the thyristor is not fully conducting the characteristics are meaningless; and if the device heats up the characteristics are no longer isothermal. A technique is presented using a fast high current (characteristic tracing) pulse superimposed on a low level, longer duration spreading pulse. The rate of rise of the fast pulse has to be optimised because irreducible self and mutual inductances in the voltage measurement gives errors which increase with di/dt and become important before the heating effect has become negligible. Careful attention to experimental detail has been coupled with numerical processing of the raw data to eliminate residual heating and di/dt effects. The method has been used in a supporting role with other experimental and numerical processing techniques for deriving high accuracy coupled electrical and thermal models of power thyristors for use in HVDC and SVC type applications.

   LOW LOSSES NEW SNUBBER CIRCUIT FOR HIGH POWER GTO INVERTER APPLICATION. TESTS AND RESULTS
By V. Gilblas; F. Favo [View]
[Download]

Abstract: Voltage source GTO lnverters need protection circuits to limit di/dt and dv/dt. These circuits, in the case of high power converters as in traction applications, have the disavantage of requiring a large room and of reducing the inverter's efficiency. This paper describes the application of a new low losses circuit in a 1.5 MW inverter used in high power locomotlve. Design criteria, tests and results are shown and dlscussed.

EPE 1991 - 19 - Session 2.8: HIGH POWER DEVICES AND PASSIVE COMPONENTS
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1991 - Conference > EPE 1991 - 19 - Session 2.8: HIGH POWER DEVICES AND PASSIVE COMPONENTS
	[return to parent folder]

	AIR-CORE VS. IRON-CORE INDUCTORS FOR POWER ELECTRONICS APPLICATIONS By A. Kusko; S. Peeran	[View] [Download]
Abstract: Designs are compared for air-core and iron-core inductors for power-electronic equipment in harmonic filters, dc link chokes, smoothing reactors, and other applications. Considerable information is available in the literature for small and large inductors, but not for intermediate sizes. The two types of inductors, of the same relative size, are compared over a dimensional and frequency range. Guidance and references are provided for the designer of power-electronic equipment .

	NON-LINEAR CURRENT TRANSFORMER FOR ACCURATE MEASUREMENT OF G.T.O. THYR!STOR TURN-OFF CHARACTERISTICS By F. J. Wakeman	[View] [Download]
Abstract: The use of Gate Turn-off Thyristors in ever higher frequency applications increases the importance of the turn-off energy and minimum off-time. The accurate measurement of both parameters is dependent upon the ability to resolve the turn-off tail current to near extinction. A non-linear current transformer has been developed which allows for the accurate measurement of tail current. When used in conjunction with an 8 bit digital storage oscilloscope the unit allows for the tail current to be measured at a lower range of amperes per volt than the rest of the current wave-form. The greater resolution of current per data point, down to some hundreds of milli-amperes for >1000A devices, permit accurate measurement of turn-off time and energy to extinction of the tail current. The results obtained with a prototype non-linear current transformer were compared against other measurement methods and found to offer a good, low cost, solution to this difficult measurement.

	TRANSIENT THERMAL RESPONSE OF POWER SEMICONDUCTORS TO SHORT POWER PULSES By Steve Clemente	[View] [Download]
Abstract: Thermal response curves used to calculate the peak junction temperature of power semiconductors are normally derived by experimental identification of the parameters of a known model. Unfortunately the model, developed many years ago, is inappropriate for large surges of short time duration, as they are encountered in present day power conditioning systems. An alterative model is derived, the limits of its accuracy are estimated, and a correction factor is elaborated. A verification of the accuracy of the two methods is also presented. Physical characteristics of popular MOSFET and IGBT dies are also provided to allow the reader to calculate the rise in junction temperature in specific applications.

	A VERY FAST POWER HYBRID MODULE WORKING IN THYRISTOR MODE By D. Lafore; J. M. Li; J. Redoutey	[View] [Download]
Abstract: Using conventional fast thyristors in current-fed resonant inverters, maximum frequency is limited to about 10 kHz due to turn-off delay time tq. Increasing the maximum frequency needs composite switches having thyristor function, made by serie connexion of a diode and a high speed controlled device (IGBT, GTO, BJT or MOS). This paper presents a power hybrid module including a cascode switch, its antisaturated driver circuit and a serie connnected diode. Design of the module is presented considering the electrical, thermal and technological problems. Results of a 10 A - 1000V module in current-fed resonant converter working in the range 100 - 300 kHz are shown.

	AN ACCURATE ONE-DIMENSIONAL MODEL FOR THE ANALYSIS OF THE TURN-OFF PERFORMANCE OF ANODE SHORTED GTO THYRISTORS By Z. Khatir; R. Lallemand	[View] [Download]
Abstract: The switching behavior of Gate Turn Off thyristor with shorted anode emitter has been calculated numerically by solving the semiconductor basic equations in an "equivalent" one-dimensional model device. It is taken into account of all significant physical semiconductor mechanisms and the interaction with a non-ideal external circuit is considered. Computations, using this model, are made on micro-computers and successfully compared with the results of measurements conducted at the INRETS's LTN-laboratory on a number of anode shorted GTO's of different origins. Short circuits between anode emitter and N-base are taken into account by an additional term in the electron recombination rate. lt is shown that the calculated switching behavior for a given device remain accurate when the external circuit is changed. The computational time of a turn-off simulation is approximately 40 minutes with a personal computer such as IBM-PC's or Macimosh Il's. Owing to the results obtained and the accurate description of the tailing current waveforms on a number of GTO's with different circuits of operation, such a simulation model is found to be a valuable tool for circuit design and device selection.

	A Driver Circuit for High Power GTO Devices By A. Brambilla, E. Dallago	[View] [Download]
Abstract: A driver circuit for GTO-thyristors applied to power converters for railway vehicles is presented. The driver studied and the realized prototype concern power GTOs (about 4500V - 3000A). The driver circuit is made up of a signal part that generates output logical signals on the basis of other input signals and a power part directly connected to the GTO. The power part is realized with DMOS mosfets rather than BJTs to give easier driving and higher commutation speed. The gate behaviour of the GTO and the behaviour of the driver are studied and outlined. Some simulations of the power circuit of the driver were done and the results are discussed and compared with the experimental ones.

	CHARACTERIZATION OF TRANSFORMER CORES USING A NEW MUTUAL IMPEDANCE FORMULA By W. G. Hurley; P. S. McNamara	[View] [Download]
Abstract: This paper describes a new method for calculating mutual and leakage impedances in transformer windings. The new formula is derived from a solution of Maxwell's Equations for coils on ferromagnetic cores. The frequency dependence of eddy current losses in the core are taken in to account and represented by the resistive component of the impedance formula. The new formula is based on the physical dimensions of the windings and core and also the magnetic permeability and electrical resistivity of the ferromagnetic core. Equivalent resistivities are derived for non-homogeneous laminated and powdered iron cores. It is shown that any core can be characterized by its magnetic permeability and equivalent electrical resistivity. The new methodology overcomes the traditional assumptions of ideal core magnetic material and negligible core losses.

	A CIRCUIT SIMULATION MODEL FOR THE HIGH POWER DIODE By P. A. Persson	[View] [Download]
Abstract: In this paper a new circuit simulation model for the high power diode is derived, that accurately describes the dynamics of the excess charge in its low doped region. This excess charge is responsible for its dynamic characteristics, and is important in most applications. The model is based on the semiconductor equations in ambipolar form and the model parameters all have physical relevance. The approach is to divide the charge into a number of subregions and describe the distribution in each one with a second degree polynomial. At the boundaries between the subregions, the distribution and its derivative have to be continuous. To each subregion belongs a charge control equation which includes terms for recombination and net supply of charge from the "outside". Other important effects, such as recombination in the emitters and the influence of free holes in the space charge layer on the voltage during reverse recovery are also included.

	GATE DRIVE UNIT FOR 2500 A - 4500 V GTO's By T. J. I. Lottman	[View] [Download]
Abstract: Gate drive circuits for GTO's have been known for some years. However with increasing power ratings of variable-speed drives for asynchronous motors, power semiconductors capable of carrying high currents and withstanding high voltages are needed. This paper presents a new generation of gate drivers for these large GTO's. Each driver consists of a galvanically independant voltage supply, optical fibres for signal transfer and a supervision circuit. GTO on/off sensing is based on gate-sensing rather then anode-sensing.

	A NEW METHOD TO ELIMINATE THE EFFECTS OF THE HIGH VOLTAGE TRANSFORMER PARASITIC ELEMENTS IN A STATIC RESONANT SUPPLY By B. Tala-Ighil; X. Tian; D. Matt; C. Glaize	[View] [Download]
Abstract: This paper describes a method to eliminate the effects induced by the high voltage transformer parasitic elements in a static resonant supply. This is done not by modifying the converter structure but by redefining the high voltage transformer structure. For this, a high voltage DC-DC converter has been designed and a model of the high voltage transformer established. The influence of the transformer parasitic elements on the structure operation is validated with the help of simulations and experiments. A method is then proposed to eliminate the effects induced by the high voltage transformer parasitic capacitance. This method has a technical advantage : it is easier to put into operation than to reduce the parasitic capacitance.

	A REGENERATIVE SNUBBER FOR THREE LEVEL HIGH POWER GTO INVERTERS By In-Dong Kim; Gyu-Hyeong Cho	[View] [Download]
Abstract: A regenerative snubber for three-level high-power GTO inverter having simple construction and high efficiency is proposed. It consists of series inductor and shunt capacitor snubbers with DC/DC converter for energy recovery trapped in the snubbers. In particular, the new DC/DC converter as an essential component of regenerative snubber has very low switching loss due to resonant operation with zero voltage switching and has small size due to high switching frequency over 10 KHz using power transistors. The proposed regenerative snubber is also thought to be applicable for other multi-level high power GTO inverters.

	WOUND COMPONENT PARASITIC ELEMENTS: CALCULATION, SIMULATION AND EXPERIMENTAL VALIDATION IN HIGH FREQUENCY POWER SUPPLY By E. Laveuve; M. Bensoam; J. P. Karadec	[View] [Download]
Abstract: The aim of this paper is to improve understanding of high frequency behaviour of wound components. Three points are specially studied: magnetic core losses, leakage inductances and stray capacitances. Equivalent circuits are set up and analytjcally justified. Experimental study of several prototypes enables magnetic core influence, winding geometry, etc to be separated. Finally, these equivalent circuits are introduced in a power electronic sirnulation software and the results are compared with the measurements acquired on a real power supply.

	INVESTIGATION ON HIGH-TEMPERATURE OPERATION FOR IGBT COMPONENTS By Ch. Schaeffer; J. P. Ferrieux; M. L. Locatelli; S. H. Gamal; S. Volut	[View] [Download]
Abstract: The purpose of this paper is to study the thermal transit of IGBT for using it in high power high frequency operations. Firstly the high temperature behaviour of silicon have been analysed above standard limits and the consequences on electrical parameters have been defined. Secondly, the components, which are able to operate in the 600 V - 400 A range, have been studied in order to evaluate losses and maximum switching frequency. Furthermore, experiments have been made on IGBT transistors. Owing to electrical junction temperature measurement, a thermal model has been established and compared with a simulated model.

	TWO-PHASE COOLING EVOLUTION OF HIGH POWER SEMICONDUCTORS By T. Jomard; U. Eckes; M. Lallemand	[View] [Download]
Abstract: Cooling by nucleate boiling is actually one of the most efficient means to remove heat from a component. For that reason, it has been used widely in the field of cooling of power electronic components. A fluid was of interest due to its various qualities: the trichlorofluoroethane. However, this latter is condemned to a short term by the Montreal protocol and the London conference. Therefore, in order to find a substitute to it, we have to note all constraints acting on the used fluid and then elaborate a schedule of trials allowing the correct grasping of the new characteristics.

	HEAT PIPE COOLING OF ELECTRONIC COMPONENTS By M. Lebailly	[View] [Download]
Abstract: The high effective thermal conductivity of a heat pipe enables heat to be transferred at high efficiency over considerable distances. For instance, for high power device within a module containing other temperature sensitive components, heat pipe connects the heat sources directly to the heat sink without temperature increasing of the other components. On the other hand, heat pipe could be used for temperature flattening in a electronic system. A heat pipe is a high thermal conductance device in which a liquid is in equilibrium with its vapor. In the evaporation area the device is cooled and in condenser the heat is evacuated to the sink ; the liquid goes from condenser to evaporator by gravity or capillary force. Now for industrial applications, XERAM have developped a large range of heat pipes for high power components cooling : with water of organic fluids as working fluid. The thermal resistance for those devices is as low as 40 to 50° K.Kw-1, and depends of air speed cooling flow and also of total power applied to the evaporator.

	SEMICONDUCTORS AT LOW TEMPERATURE By J. F. Kärner; H. W. Lorenzen; W. Rehm	[View] [Download]
Abstract: At present, power diodes are operated at 4.2 K in order to protect superconduting accelerator magnets from quenches. A Further uso might be the protection of the single coils or coil sections of superconducting magnetic energy storage (SMES) plants. As the reactive coil voltage at transient operation exceeds the threshold voltage of diodes by far, thyristors will come to be used instead. The contribution presents the results of experimental investigations on a series of thyristors at 77 K; it also reports on preliminary tests carried out at 4.2 K. A short description of the test set-up to be installed at the TU München for extensive measurements at 4.2 K is given.

	BIDIRECTIONAL OPTOELECTRONIC THYRISTORS RATED AT 80 A, 1200 V By N. A. Tetervova; R. I. Rybak; V. A. Zlobin; Z. I. Kafengauz	[View] [Download]
Abstract: The paper presents results of investigations aimed at designing production prototypes of bidirectional optoelectronic thyristors (optotriacs) rated at a current to 80 A and a repetitive peak voltage to 1,200V. Main geometrical and electrophysical parameters of optotriac structures are calculated, and the interconnection of those with photosensitivity and dynamic characteristics is studied. By using infra-red equipment and a method of scanning electron microscopy specific features of switching processes in a turned-on-by-light, five-layer n-p-n-p-n structure having an amplifying gate are investigated. On the basis of the investigations a design and technological methods of fabricating high-power optotriacs are developed. Optotriac prototypes have been fabricated and tested.

	THE DC-LINK INDUCTOR SINGLE LEG CAPACITOR ENERGY RECOVERING SNUBBER By Victor Manuel Guzman; Maria Gimenez De Guzman; Peter Bowler	[View] [Download]
Abstract: A snubber configuration having minimum component count and minimum losses is presented for inverters. Component count reduction is achieved by sharing a single snubber capacitor between each pair of power switches in each leg and relocating leg inductances to the dc-link, where they are shared by all inverter legs. This is particulary interesting when using devices in power pack modules. In high load çurrent operation no net energy is transfered to the snubber, giving no losses snubber operation. At low load, excess energy is stored as current in the inductors. A way to return this energy to the supply is presented, thereby achieving minimum losses under all load conditions.

	STUDIES OF REVERSE RECOVERY EFFECTS IN POWER FAST RECOVERY DIODES By G. Vaher; V. Ruhamkin; M. Tarma	[View] [Download]
Abstract: The possibilities of controlling the minority carrier lifetime of electron and proton irradiation and platinum diffusion are compared. The investigations the reverse recovery parameters in the range of temperature 25°c...180°c with the interval 10°c point to the increasing trr with temperature by abrupt steps. The lowest values of trr (1.3 ... 1.5 us) and Krr (1.1 ... 1.2) are obtained by proton irradiation and one side platinum diffusion as a result of low lifetime value in P+P emitter.

	POWER ELECTRONIC DEVICES AND THEIR APPLICATION TO TRANSMISSION AND INDUSTRY By G. R. Clark; G. A. Ferry	[View] [Download]
Abstract: The rapid development of power electronic devices has been matched by the utilisation of these devices, in an ever widening variety of applications. This paper describes the essential characteristics of the principal devices, currently available and under development, and their relevance to applications in the field of electrical power engineering. Several such applications - to power transmission, industrial processes and transportation - are discussed in terms of their power electronic device requirements, the benefits gained from advances in device technology and their influence on device development.

	MODELLING OF HIGH POWER THYRISTORS UP TO SURGE LEVELS FOR OBTAINING V-I CHARACTERISTICS By . Y. A. Shammas; J. K. Chester	[View] [Download]
Abstract: There are situations where a knowledge of the isothermal V-I characteristics of high power thyristors up to high current levels can be very useful. Obtaining such characteristics is immediately made difficult by the time taken for a large device to become fully conducting (the spreading time) and the need to prevent it from heating up. If the thyristor is not fully conducting the characteristics are meaningless; and if the device heats up the characteristics are no longer isothermal. A technique is presented using a fast high current (characteristic tracing) pulse superimposed on a low level, longer duration spreading pulse. The rate of rise of the fast pulse has to be optimised because irreducible self and mutual inductances in the voltage measurement gives errors which increase with di/dt and become important before the heating effect has become negligible. Careful attention to experimental detail has been coupled with numerical processing of the raw data to eliminate residual heating and di/dt effects. The method has been used in a supporting role with other experimental and numerical processing techniques for deriving high accuracy coupled electrical and thermal models of power thyristors for use in HVDC and SVC type applications.

	LOW LOSSES NEW SNUBBER CIRCUIT FOR HIGH POWER GTO INVERTER APPLICATION. TESTS AND RESULTS By V. Gilblas; F. Favo	[View] [Download]
Abstract: Voltage source GTO lnverters need protection circuits to limit di/dt and dv/dt. These circuits, in the case of high power converters as in traction applications, have the disavantage of requiring a large room and of reducing the inverter's efficiency. This paper describes the application of a new low losses circuit in a 1.5 MW inverter used in high power locomotlve. Design criteria, tests and results are shown and dlscussed.