EPE Association: EPE 1987 - 35 - Dialogue Session 5.1: SYSTEM DESIGN

EPE 1987 - 35 - Dialogue Session 5.1: SYSTEM DESIGN
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1987 - Conference > EPE 1987 - 35 - Dialogue Session 5.1: SYSTEM DESIGN

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   OPERATION AND DIMMING CONTROL OF HID LAMPS WITH SOLID-STATE PWM CHOPPER
By Osamu Miyashita; Tadao Fujimaki [View]
[Download]

Abstract: High intensity discharge (HID) mercury lamps have been widely employed mainly because of their high efficacy, very long Iife, and good lumen maintenance in industrial and medical applications as well as in general illuminations. The conventional ballast for HID lamps is an AC circuit with a reactor, a capacitor or mostly a Ieakage transformer to obtain stable operation. However such kinds of operation are not applicable directly to dimmimg control of the lamp. This paper proposes a new practical method of starting and controlling the luminous flux of HID lamps with a current-source PWM chopper. The experimental results show that the control method will be suitable for a practical ballast.

   MICROCOMPUTER-BASED CONTROL SYSTEM FOR THE HEATING PROCESS LINE
By Maciej Tondos; Herbert Widlok [View]
[Download]

Abstract: The paper presents a solution of control system for several (even 50) thyrisor power supplies working in resistance heating process line. The main tasks to be perfomed by the microprocessor-based controller are: measuring and stabilization of temperature in all thyristor power supplies and providing heating-up with puted constant temperature-rise. Also individual corrections of temperatures for each feeder can be provided. In the present paper a procedure of technical realization of all main functions is presented together with a short description of hardware and software structure. In the end some results of tests at laboratory test stand are shown. The main application of this described system is thyristor power supplies for platinic bushings in glass industry.

   COMPUTER-AIDED TRANSIENT ANALYSIS OF POWER-ELECTRONIC DC-MOTOR DRIVES: APPLICATION TO 250-600 LOCOMOTIVE OF SPANISH NATIONAL RAILWAYS (RENFE)
By J. A. Jiménez; A. Pérez-Coyto [View]
[Download]

Abstract: An efficient method for the transitory analysis of biphase chopper equipment on tractive units, is described using SPICE2 program with a modified diode model. Transient waveforms of chopper equipment on RENFE 250-600 locomotives are calculated only with data sheets. The results are compared with those obtained on testing platform.

   LIGHT WEIGHT DC/DC CONVERTERS FOR HIGH-SPEED TRACTION APPLICATIONS
By A. Farini; F. Fuga; R. Manigrasso; M. Ubaldini [View]
[Download]

Abstract: The Italian high speed traction system forsees the use of a supply system with a dc medium voltage (12 kV), higher than the actual one (3kV), in order to improve the captation on board of the current and to maintain a conveniant distance between substations. The new high speed system locomotives, which should be compatible with the old supply system, will require an on-board dc/dc power converter with ratio 12kV / 3kV and power in the order of some MVA. The weight of the converter should be kept low because the weight of the locomotive must be reduced as much as possible in order to limit the dynamic stress of the rails at high speed (300 km/h). This paper presents two medium frequency power transformers (1kHz - 1.1 MVA) specially designed for a dc/dc converter (12 kV / 3kV). One has a core cooled by means of radiators filled with boiling freon and the other by means of forced circulating oil. Experimental results of two prototypes are also produced.

   COMPENSATION OF THE REACTIVE POWER BY MEANS OF A CURRENT-CONTROLLED TRANSISTOR INVERTER
By E. Tironi; D. Zaninelli; G. Ubezio [View]
[Download]

Abstract: This paper concerns a device for the rapid compensation of the reactive power absorbed by a single-phase load. The philosophy underlying the proposed principle is radically different from the more traditional approaches. The system consists of a current-controlled transistor inverter which can inject into the network the quadrature component of the current absorbed by the load. During the investigation, three twin-state techniques for the on-off control of the current have been identified: fixed frequency, constant transistor shutdown time, constant current ripple. The theoretical and experimental studies conducted so far have identified the last two techniques as the better ones and, in particular, that of the constant ripple. This is because with a given maximum transistor commutation frequency it is possible to inject into the network currents with a lower harmonic content. Faster response and continuity of modulation of the reactive power represent further particular characteristics of the device. In the closing part of the paper we mention briefly the possibilities offered by the use of three-state modulation techniques as well as possible three-phase applications of the proposed system.

   ANALYSIS OF UM-CONCEPT TYPE THYRISTOR PHASE-CONTROLLED VAR COMPENSATOR
By Ji-Yan Chen [View]
[Download]

Abstract: In this paper, the steady-state performance of UM-concept thyristor phase-controlled VAR compensator (developed by University of Manitoba,Canada) is studied by theoretical analysis and computer simulation. It is found that the UM-concept type is itself a subharmonic source which may excite subharmonic oscillations and overvoltages in electric power systems. It is also found, however, the fundamental component of the current and the reactive power delivered by UM-concept type are linear with respect to igniting angle, and then, the expression derived in this paper is more simple than the formula offered by other authors.

   SUB-SYNCHRONOUS CONVERTER CASCADE WITH AMPLITUDE MODULATION OF INVERTED CURRENT
By L. Ribickis; J. Greywoolis; I. Avkshtol [View]
[Download]

Abstract: Sub-synchronous converter cascade (s.s.c.c.) inverter unfavourable influence on network may be reduced by amplitude modulation (A.M.) use. In this text series and parallel connections of inverters in rotor circuit of induction motor (I.M.) are considered to find the opportunities of both network current shape approach to sinusoid and I.M. losses reduction. Attention is largely concentrated on the design of power circuit. The results of simulation are given.

   SIMULATOR STUDY OF OVERVOLTAGES DUE TO CONVERTER-BLOCKING IN HVDC LINK
By M. M. Atout [View]
[Download]

Abstract: This paper presents a study of overvoltages generated on a HVDC poles resulting from converter-blocking with misfiring of by-pass valve; which injects an AC voltage component into the DC line. The magnitude of this component depends on the nature of fault, DC line impedance characteriestic, DC smoothing reactor, AC network short circuit power and the converter control system parameters. The influence of these parameters on this abnormal overvoltage is discussed. This phenomena is studied using a HVDC simulator for a point to point DC link and for a multiterminal transmission link having three terminal converter stations. The summary of the obtained results shown in this paper, indicates that the abnormal overvoltages may be suppressed by the selection of appropriate DC system parameters, by installation of auxillary reverse-bias diode or by installation of a damping circuit tor the DC lines. Also the proper and optimum design of the central loop parameters gives an important damping effect on these overvoltages.

EPE 1987 - 35 - Dialogue Session 5.1: SYSTEM DESIGN
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1987 - Conference > EPE 1987 - 35 - Dialogue Session 5.1: SYSTEM DESIGN
	[return to parent folder]

	OPERATION AND DIMMING CONTROL OF HID LAMPS WITH SOLID-STATE PWM CHOPPER By Osamu Miyashita; Tadao Fujimaki	[View] [Download]
Abstract: High intensity discharge (HID) mercury lamps have been widely employed mainly because of their high efficacy, very long Iife, and good lumen maintenance in industrial and medical applications as well as in general illuminations. The conventional ballast for HID lamps is an AC circuit with a reactor, a capacitor or mostly a Ieakage transformer to obtain stable operation. However such kinds of operation are not applicable directly to dimmimg control of the lamp. This paper proposes a new practical method of starting and controlling the luminous flux of HID lamps with a current-source PWM chopper. The experimental results show that the control method will be suitable for a practical ballast.

	MICROCOMPUTER-BASED CONTROL SYSTEM FOR THE HEATING PROCESS LINE By Maciej Tondos; Herbert Widlok	[View] [Download]
Abstract: The paper presents a solution of control system for several (even 50) thyrisor power supplies working in resistance heating process line. The main tasks to be perfomed by the microprocessor-based controller are: measuring and stabilization of temperature in all thyristor power supplies and providing heating-up with puted constant temperature-rise. Also individual corrections of temperatures for each feeder can be provided. In the present paper a procedure of technical realization of all main functions is presented together with a short description of hardware and software structure. In the end some results of tests at laboratory test stand are shown. The main application of this described system is thyristor power supplies for platinic bushings in glass industry.

	COMPUTER-AIDED TRANSIENT ANALYSIS OF POWER-ELECTRONIC DC-MOTOR DRIVES: APPLICATION TO 250-600 LOCOMOTIVE OF SPANISH NATIONAL RAILWAYS (RENFE) By J. A. Jiménez; A. Pérez-Coyto	[View] [Download]
Abstract: An efficient method for the transitory analysis of biphase chopper equipment on tractive units, is described using SPICE2 program with a modified diode model. Transient waveforms of chopper equipment on RENFE 250-600 locomotives are calculated only with data sheets. The results are compared with those obtained on testing platform.

	LIGHT WEIGHT DC/DC CONVERTERS FOR HIGH-SPEED TRACTION APPLICATIONS By A. Farini; F. Fuga; R. Manigrasso; M. Ubaldini	[View] [Download]
Abstract: The Italian high speed traction system forsees the use of a supply system with a dc medium voltage (12 kV), higher than the actual one (3kV), in order to improve the captation on board of the current and to maintain a conveniant distance between substations. The new high speed system locomotives, which should be compatible with the old supply system, will require an on-board dc/dc power converter with ratio 12kV / 3kV and power in the order of some MVA. The weight of the converter should be kept low because the weight of the locomotive must be reduced as much as possible in order to limit the dynamic stress of the rails at high speed (300 km/h). This paper presents two medium frequency power transformers (1kHz - 1.1 MVA) specially designed for a dc/dc converter (12 kV / 3kV). One has a core cooled by means of radiators filled with boiling freon and the other by means of forced circulating oil. Experimental results of two prototypes are also produced.

	COMPENSATION OF THE REACTIVE POWER BY MEANS OF A CURRENT-CONTROLLED TRANSISTOR INVERTER By E. Tironi; D. Zaninelli; G. Ubezio	[View] [Download]
Abstract: This paper concerns a device for the rapid compensation of the reactive power absorbed by a single-phase load. The philosophy underlying the proposed principle is radically different from the more traditional approaches. The system consists of a current-controlled transistor inverter which can inject into the network the quadrature component of the current absorbed by the load. During the investigation, three twin-state techniques for the on-off control of the current have been identified: fixed frequency, constant transistor shutdown time, constant current ripple. The theoretical and experimental studies conducted so far have identified the last two techniques as the better ones and, in particular, that of the constant ripple. This is because with a given maximum transistor commutation frequency it is possible to inject into the network currents with a lower harmonic content. Faster response and continuity of modulation of the reactive power represent further particular characteristics of the device. In the closing part of the paper we mention briefly the possibilities offered by the use of three-state modulation techniques as well as possible three-phase applications of the proposed system.

	ANALYSIS OF UM-CONCEPT TYPE THYRISTOR PHASE-CONTROLLED VAR COMPENSATOR By Ji-Yan Chen	[View] [Download]
Abstract: In this paper, the steady-state performance of UM-concept thyristor phase-controlled VAR compensator (developed by University of Manitoba,Canada) is studied by theoretical analysis and computer simulation. It is found that the UM-concept type is itself a subharmonic source which may excite subharmonic oscillations and overvoltages in electric power systems. It is also found, however, the fundamental component of the current and the reactive power delivered by UM-concept type are linear with respect to igniting angle, and then, the expression derived in this paper is more simple than the formula offered by other authors.

	SUB-SYNCHRONOUS CONVERTER CASCADE WITH AMPLITUDE MODULATION OF INVERTED CURRENT By L. Ribickis; J. Greywoolis; I. Avkshtol	[View] [Download]
Abstract: Sub-synchronous converter cascade (s.s.c.c.) inverter unfavourable influence on network may be reduced by amplitude modulation (A.M.) use. In this text series and parallel connections of inverters in rotor circuit of induction motor (I.M.) are considered to find the opportunities of both network current shape approach to sinusoid and I.M. losses reduction. Attention is largely concentrated on the design of power circuit. The results of simulation are given.

	SIMULATOR STUDY OF OVERVOLTAGES DUE TO CONVERTER-BLOCKING IN HVDC LINK By M. M. Atout	[View] [Download]
Abstract: This paper presents a study of overvoltages generated on a HVDC poles resulting from converter-blocking with misfiring of by-pass valve; which injects an AC voltage component into the DC line. The magnitude of this component depends on the nature of fault, DC line impedance characteriestic, DC smoothing reactor, AC network short circuit power and the converter control system parameters. The influence of these parameters on this abnormal overvoltage is discussed. This phenomena is studied using a HVDC simulator for a point to point DC link and for a multiterminal transmission link having three terminal converter stations. The summary of the obtained results shown in this paper, indicates that the abnormal overvoltages may be suppressed by the selection of appropriate DC system parameters, by installation of auxillary reverse-bias diode or by installation of a damping circuit tor the DC lines. Also the proper and optimum design of the central loop parameters gives an important damping effect on these overvoltages.