EPE Association: EPE 1989 - 34 - Dialogue Session 2.1: GTO's AND BIPOLAR TRANSISTORS

EPE 1989 - 34 - Dialogue Session 2.1: GTO's AND BIPOLAR TRANSISTORS
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1989 - Conference > EPE 1989 - 34 - Dialogue Session 2.1: GTO's AND BIPOLAR TRANSISTORS

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   FAULT-TOLERANT PROCEDURE FOR DATA-TRANSMISSION BETWEEN THE SIGNAL ELECTRONICS AND THE GATE TRIGGERING UNITS IN GTO POWER CONVERTERS
By M. Peppel [View]
[Download]

Abstract: In high-power GTO converters for traction applications, transfer of the control command and a checkback signal between the control system and the GTO gate units via optical waveguides is nowadays state of the art. The general signal convention for the control command path is "light on" = "GTO should conduct", "light off" = "GTO should block". On the feedback path, as a rule "light on" = "GTO blocking", "light off" = "GTO status unknown". This mode does not make it possible to recognise faults and also affords little checkback information on the system status. The present paper describes a transmission procedure that is fault-tolerant and also affords more status information. This procedure consists of transmission codes for the control command and checkback signals and the code/decode and fault identification methods. It is built up on the principles of: as simple as possible - quick transmission - reduced electronic circuitry for coding and decoding. This procedure makes it possible to monitor the entire "coder => optical fibre => receiver => GTO gate unit => GTO => status identification => optical waveguide => receiver => decoder" loop for proper functioning.

   THE INFLUENCE OF GATE DRIVE CIRCUITS ON THE SWITCHING BEHAVIOUR OF LARGE GATE TURN-OFF THYRISTORS (GOTS)
By Reinhard Sievers; J. Schmidt [View]
[Download]

Abstract: First a universal gate drive circuit for GTOs with turn-off currents up to 1000 A at a maximum switching frequency of 5 - 10 kHz is presented. The gate drive circuit disposes of an integrated, galvanically independant voltage supply. For reliability's sake opticaI fibres were used as signal transfer. On the gate drive circuit also supervision functions are integrated. Second investigation results with variable gate drive currents of GTOs are described. lt appears that the amplitude of the turn-on gate drive current considerably influences both the gate-controlled delay time and the turn-on time. So an increase of the gate current diminishes the turn-on losses, thus enabling a higher switching frequency. When turning-off GTOs the storage time as well as the fall time of the GTOs is increasing while the rate of negative gate current rise decreases.

   A NEW SNUBBER FOR GTO-APPLICATIONS WITH ENERGY RECOVERY BY AN ACTIVE / PASSIVE CIRCUIT
By Hans Schamböck; Karl Schiftner [View]
[Download]

Abstract: A new snubber network configuration for chopper, 2 or 3 level PWM inverter application with GTO thyristors or power transistors permits snubber energy recovery. Two kinds of snubber energy recovery are possible:
* Active recovery towards an auxiliary voltage source. Total energy recovery is possible. The principle of the circuit is easy, but the necessary equipment of the voltage source is very high.
* Passive recovery by an energy-recovery transformer (replacing the DC/DC converter). A substantial part of snubber energy can be recovered. The remaining energy is dissipated within a resistor.
For practical purposes, use of passive recovery is reliable and reasonable.

   LOW LOSS GATE DRIVE CIRCUIT FOR HIGH POWER GTO-THYRISTORS
By Gert Fregien [View]
[Download]

Abstract: The paper presents a gate drive circuit which uses different negative voltage sources for turning off high power GTO-thyristors. This circuit allows to shorten the storage times, to install long gate leads, and to reduce the size of the gate drive unit due to reduced gate trigger power. It can be employed in applications operating at high switching frequencies, i. e. quasiresonant inverters, or in applications involving long distances between GTO and gate drive circuit. The applicability of the circuit and its control method are proved experimentally. The main issue lays on demonstrating the gate turn off power reduction.

   REDUCTION OF LOSSES IN DRIVE CIRCUITS FOR BIPOLAR POWER TRANSISTORS
By L. Sack [View]
[Download]

Abstract: By use of a DC/DC-converter the nearly lossless production of base current is possible. Aspects of implementation of such a converter in the base drive circuit are considered. Effects of base current ripple on different types of power transistors are represented as well as measures for filtering and control strategies. Experimental results show the application on single transistors and darlingtons. Compared with conventional drive circuits the power consumption can be reduced drastically. In the case of darlinoton a profit of maximum current and frequency is reachable.

   LOW POWER HYBRID INVERTERS FOR HIGH VOLUME PRODUCTION
By R. Gabriel; M. Strehlow [View]
[Download]

Abstract: Inverter fed AC drives up to 1 kW could not gain market shares outside industrial applications. The reason is the cost disadvantage compared to conventional collector motor drives. The only way to get an approach to lower cost, better performance and higher reliability is to reduce the expense by the means of microelectronics. It will be shown, that it is possible to decrease the part count of an inverter near one magnitude by integration of drive electronics for the power transistors and on the control side by the integration of all control needed for an inverter in a single chip. During this approach a phenomenon relied to the destruction mechanism of MOS- transistors was found, which will be described first.

   PROBLEMS AND SOLUTIONS IN THE USE OF ULTRAFAST SWITCHING HV BIPOLAR TRANSISTORS IN PWM INVERTERS
By P. Zwanziger [View]
[Download]

Abstract: Bipolar transistors of the new generation with ring emitter structure make possible to operate at high switching frequencies without snubbers. The first modules (SIRET®) in totem pole configuration with high current carrying capacity and blocking ability, with three-stage Darlington configurations and the appropriate diodes in hybrid interconnection assemblies, are now available and, through very short switching times, permit increased equipment efficiencies even at higher switching frequencies. This paper deals with special proposals necessary for ensuring disturbance-free application of these elements. They include the suppression of parasitic oscillations during ultrafast switching, measures for assuring ample dV/dt- stability and the investigation of permissible operating ranges at short-circuit. Special attention is also given on the optimization of the transistor switching speed with due attention to the characteristics of the free-wheeling diode, the thermal resistance conditions and the junction temperature coupling of transistor chip and diode chip.

   GTO CHARACTERIZATION FOR THE CALCULATION OF THEIR PROTECTION BY FUSES
By J. F. de Palma; R. Ehlinger; J. J. Rousseau; J. P. Chante; R. Deshayes; P. Epron [View]
[Download]

Abstract: An accurate measurement of the surge current in GTOs allows to optimize their applications and enables the determination of an efficient protection with fuses. The intent of this study is to develop an easy and non-destructive method in order to characterize the surge current. The characterization is based on the analysis of the anode-cathode voltage Vak. Moreover we bring outr that even though the usual law for classical thyristor I4*t = const remains valid for the GTO, it leads to a misestimation of the surge current for short period pulses.

   OVERCURRENT PROTECTION AND SWITCHING AID FOR POWER DARLINGTONS: AN UNIQUE APPROACH
By A. R. Quintas; J. A. Faria; A. P. Martins: A. S. Araujo; J. P. Silva [View]
[Download]

Abstract: This paper presents a new approach for overcurrent protection and switching aid of Power Darlington Transistors used in a UPS inverter. The approach come through specific requirements and characteristics of UPS and Power Darlington Transistors. It is noted that storage time and output transformer introduce low frequency distortion. The minimun output filter for this application was obtained for a switching frequency near 2 KHz. At this level switching losses are small when compared with total losses. This fact greatly simplifies the switching aid circuits, being then possible to reduce it to a voltage clamp and a series inductance. The circuit reveals to be cost effective and reliable and uses only low performance/cost components. Experimental results are presented for a 40 KVA UPS that was conceived at Porto University and is now manufactured by a portuguese company.

   INVESTIGATION ON FORCED-COMMUTATED GTO-THYRISTORS: THE MIXED TURN-OFF THYRISTORS
By M. Bourahla; C. Glaize [View]
[Download]

Abstract: This paper presents the mixed turn-off thyristor (MTO-thyristor). It is a GTO-thyristor operating in a power structure using conjointly the technique of the forced commutation (auxiliary circuit) and the assistance of the gate (charge extraction). The dynamic behaviour of the MTO-thyristor at turn-off is investigated. The interest when using a GTO-thyristor with a mixed cornmand is the obtention of a reduced turn-off time with reduced switching turn-off losses.

   HIGH POWER GTO'S WITH FREE-FLOATING SILICON TECHNOLOGY
By A. Schweizer; A. A. Jaecklin; P. Streit [View]
[Download]

Abstract: The free floating silicon technology (FFST) is very well adapted to modern large area semiconductor device fabrication and permits application of advanced cathode and anode emitter structures as well as improved lifetime control methods for turn-off devices with reduced switching energies. A camparison with gate turn-off thyristors (GTO's) in alloyed technique shows that already present-day devices using FFST exhibit an improved trade-off between static and dynamic power losses without affecting the performance in surge current, thermal cycling capability and thermal resistance. For the next generation of high power turn-off devices, requiring finer structures, the advantages of FFST over alloying technique are expected to be even more important.

EPE 1989 - 34 - Dialogue Session 2.1: GTO's AND BIPOLAR TRANSISTORS
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1989 - Conference > EPE 1989 - 34 - Dialogue Session 2.1: GTO's AND BIPOLAR TRANSISTORS
	[return to parent folder]

	FAULT-TOLERANT PROCEDURE FOR DATA-TRANSMISSION BETWEEN THE SIGNAL ELECTRONICS AND THE GATE TRIGGERING UNITS IN GTO POWER CONVERTERS By M. Peppel	[View] [Download]
Abstract: In high-power GTO converters for traction applications, transfer of the control command and a checkback signal between the control system and the GTO gate units via optical waveguides is nowadays state of the art. The general signal convention for the control command path is "light on" = "GTO should conduct", "light off" = "GTO should block". On the feedback path, as a rule "light on" = "GTO blocking", "light off" = "GTO status unknown". This mode does not make it possible to recognise faults and also affords little checkback information on the system status. The present paper describes a transmission procedure that is fault-tolerant and also affords more status information. This procedure consists of transmission codes for the control command and checkback signals and the code/decode and fault identification methods. It is built up on the principles of: as simple as possible - quick transmission - reduced electronic circuitry for coding and decoding. This procedure makes it possible to monitor the entire "coder => optical fibre => receiver => GTO gate unit => GTO => status identification => optical waveguide => receiver => decoder" loop for proper functioning.

	THE INFLUENCE OF GATE DRIVE CIRCUITS ON THE SWITCHING BEHAVIOUR OF LARGE GATE TURN-OFF THYRISTORS (GOTS) By Reinhard Sievers; J. Schmidt	[View] [Download]
Abstract: First a universal gate drive circuit for GTOs with turn-off currents up to 1000 A at a maximum switching frequency of 5 - 10 kHz is presented. The gate drive circuit disposes of an integrated, galvanically independant voltage supply. For reliability's sake opticaI fibres were used as signal transfer. On the gate drive circuit also supervision functions are integrated. Second investigation results with variable gate drive currents of GTOs are described. lt appears that the amplitude of the turn-on gate drive current considerably influences both the gate-controlled delay time and the turn-on time. So an increase of the gate current diminishes the turn-on losses, thus enabling a higher switching frequency. When turning-off GTOs the storage time as well as the fall time of the GTOs is increasing while the rate of negative gate current rise decreases.

	A NEW SNUBBER FOR GTO-APPLICATIONS WITH ENERGY RECOVERY BY AN ACTIVE / PASSIVE CIRCUIT By Hans Schamböck; Karl Schiftner	[View] [Download]
Abstract: A new snubber network configuration for chopper, 2 or 3 level PWM inverter application with GTO thyristors or power transistors permits snubber energy recovery. Two kinds of snubber energy recovery are possible: * Active recovery towards an auxiliary voltage source. Total energy recovery is possible. The principle of the circuit is easy, but the necessary equipment of the voltage source is very high. * Passive recovery by an energy-recovery transformer (replacing the DC/DC converter). A substantial part of snubber energy can be recovered. The remaining energy is dissipated within a resistor. For practical purposes, use of passive recovery is reliable and reasonable.

	LOW LOSS GATE DRIVE CIRCUIT FOR HIGH POWER GTO-THYRISTORS By Gert Fregien	[View] [Download]
Abstract: The paper presents a gate drive circuit which uses different negative voltage sources for turning off high power GTO-thyristors. This circuit allows to shorten the storage times, to install long gate leads, and to reduce the size of the gate drive unit due to reduced gate trigger power. It can be employed in applications operating at high switching frequencies, i. e. quasiresonant inverters, or in applications involving long distances between GTO and gate drive circuit. The applicability of the circuit and its control method are proved experimentally. The main issue lays on demonstrating the gate turn off power reduction.

	REDUCTION OF LOSSES IN DRIVE CIRCUITS FOR BIPOLAR POWER TRANSISTORS By L. Sack	[View] [Download]
Abstract: By use of a DC/DC-converter the nearly lossless production of base current is possible. Aspects of implementation of such a converter in the base drive circuit are considered. Effects of base current ripple on different types of power transistors are represented as well as measures for filtering and control strategies. Experimental results show the application on single transistors and darlingtons. Compared with conventional drive circuits the power consumption can be reduced drastically. In the case of darlinoton a profit of maximum current and frequency is reachable.

	LOW POWER HYBRID INVERTERS FOR HIGH VOLUME PRODUCTION By R. Gabriel; M. Strehlow	[View] [Download]
Abstract: Inverter fed AC drives up to 1 kW could not gain market shares outside industrial applications. The reason is the cost disadvantage compared to conventional collector motor drives. The only way to get an approach to lower cost, better performance and higher reliability is to reduce the expense by the means of microelectronics. It will be shown, that it is possible to decrease the part count of an inverter near one magnitude by integration of drive electronics for the power transistors and on the control side by the integration of all control needed for an inverter in a single chip. During this approach a phenomenon relied to the destruction mechanism of MOS- transistors was found, which will be described first.

	PROBLEMS AND SOLUTIONS IN THE USE OF ULTRAFAST SWITCHING HV BIPOLAR TRANSISTORS IN PWM INVERTERS By P. Zwanziger	[View] [Download]
Abstract: Bipolar transistors of the new generation with ring emitter structure make possible to operate at high switching frequencies without snubbers. The first modules (SIRET®) in totem pole configuration with high current carrying capacity and blocking ability, with three-stage Darlington configurations and the appropriate diodes in hybrid interconnection assemblies, are now available and, through very short switching times, permit increased equipment efficiencies even at higher switching frequencies. This paper deals with special proposals necessary for ensuring disturbance-free application of these elements. They include the suppression of parasitic oscillations during ultrafast switching, measures for assuring ample dV/dt- stability and the investigation of permissible operating ranges at short-circuit. Special attention is also given on the optimization of the transistor switching speed with due attention to the characteristics of the free-wheeling diode, the thermal resistance conditions and the junction temperature coupling of transistor chip and diode chip.

	GTO CHARACTERIZATION FOR THE CALCULATION OF THEIR PROTECTION BY FUSES By J. F. de Palma; R. Ehlinger; J. J. Rousseau; J. P. Chante; R. Deshayes; P. Epron	[View] [Download]
Abstract: An accurate measurement of the surge current in GTOs allows to optimize their applications and enables the determination of an efficient protection with fuses. The intent of this study is to develop an easy and non-destructive method in order to characterize the surge current. The characterization is based on the analysis of the anode-cathode voltage Vak. Moreover we bring outr that even though the usual law for classical thyristor I4*t = const remains valid for the GTO, it leads to a misestimation of the surge current for short period pulses.

	OVERCURRENT PROTECTION AND SWITCHING AID FOR POWER DARLINGTONS: AN UNIQUE APPROACH By A. R. Quintas; J. A. Faria; A. P. Martins: A. S. Araujo; J. P. Silva	[View] [Download]
Abstract: This paper presents a new approach for overcurrent protection and switching aid of Power Darlington Transistors used in a UPS inverter. The approach come through specific requirements and characteristics of UPS and Power Darlington Transistors. It is noted that storage time and output transformer introduce low frequency distortion. The minimun output filter for this application was obtained for a switching frequency near 2 KHz. At this level switching losses are small when compared with total losses. This fact greatly simplifies the switching aid circuits, being then possible to reduce it to a voltage clamp and a series inductance. The circuit reveals to be cost effective and reliable and uses only low performance/cost components. Experimental results are presented for a 40 KVA UPS that was conceived at Porto University and is now manufactured by a portuguese company.

	INVESTIGATION ON FORCED-COMMUTATED GTO-THYRISTORS: THE MIXED TURN-OFF THYRISTORS By M. Bourahla; C. Glaize	[View] [Download]
Abstract: This paper presents the mixed turn-off thyristor (MTO-thyristor). It is a GTO-thyristor operating in a power structure using conjointly the technique of the forced commutation (auxiliary circuit) and the assistance of the gate (charge extraction). The dynamic behaviour of the MTO-thyristor at turn-off is investigated. The interest when using a GTO-thyristor with a mixed cornmand is the obtention of a reduced turn-off time with reduced switching turn-off losses.

	HIGH POWER GTO'S WITH FREE-FLOATING SILICON TECHNOLOGY By A. Schweizer; A. A. Jaecklin; P. Streit	[View] [Download]
Abstract: The free floating silicon technology (FFST) is very well adapted to modern large area semiconductor device fabrication and permits application of advanced cathode and anode emitter structures as well as improved lifetime control methods for turn-off devices with reduced switching energies. A camparison with gate turn-off thyristors (GTO's) in alloyed technique shows that already present-day devices using FFST exhibit an improved trade-off between static and dynamic power losses without affecting the performance in surge current, thermal cycling capability and thermal resistance. For the next generation of high power turn-off devices, requiring finer structures, the advantages of FFST over alloying technique are expected to be even more important.