EPE Association: EPE 1987 - 05 - Lecture Session 1.05: CONVERTERS (I)

EPE 1987 - 05 - Lecture Session 1.05: CONVERTERS (I)
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   DIRECT DIGITAL CONTROL OF FOUR-QUADRANT POWER CONVERTER
By T. Seger; M. Wächter [View]
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Abstract: BBC has equipped eight four axle multi-purpose main-line locomotives Re 4/4 with asynchronous induction motor drives fed by voltage source inverters. Input power conversion is achieved by means of a Four-Quadrant Power Converter. Both the inverter and the converter are equipped with GTO's and fully controlled by four micro-controllers. Two of them are closely linked and handle the control algorithms of the Four-Quadrant Power Converter. One uP is for line synchronization and voltage control, the second uP handles all current control tasks and PWM of the three secondary loops. Design objectives were a good power factor ( = 1) and fast dynamic response. The extended possibilities of the MICAS(R) automation system allow the implementation of better control technology and the integration of extended diagnostic capability during normal operation of the drive system. As a result, the first two locomotives show good dynamic behaviour and very low harmonic content in the line current.

   THE DESIGN OF A HIGH STABILITY (10 PPM) BI-POLAR 700W CONTINUOUSLY VARIABLE OUTPUT SWITCHED MODE POWER CONVERTER
By R. Forrest; C. D. M. Oates [View]
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Abstract: CERN, the European Centre for Particle Physics Research, had a requirement for a large number of converters to power corrector magnets for LEP (Large Electron Positron Collider) which is under construction at Geneva. The work was done in collaboration with GEC Transmission and Distribution Projects Limited, who designed the power converter and voltage control, following a technical specification issued by CERN. The precision current control capable of 10 ppm stability on the 5 Amp output was designed by CERN. Various design aspects are discussed, including the design of the power circuit, the PWM control, filtering and the servo control loops. Particular consideration is given to aspects of SMPS which have prevented them being used in high precision requirements until now, ie loop stability versus bandwidth, ripple filtering and RFI emission and susceptibility.

   THE EVOLUTION OF UPS-SYSTEMS OVER VARIOUS GENERATIONS AND THEIR FURTHER DEVELOPMENT
By H. E. Schweickardt; H. Beeler [View]
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Abstract: Today, uninterruptible power supply (UPS) systems have attained a position of ever increasing importance. The present range of UPS equipment permits optimum employment for various applications. This paper shows the development of the UPS from the rotating systems to the standard static equipment of today. Concepts and methods of operation common for today are presented. Progress made on the static UPS equipment since the first generation up to today's designs is illustrated by comparing some of the major features. The most important trends for future equipment developrnent are elucidated.

   DEVELOPMENT AND CHARACTERISTICS OF BATTERY-FED, HIGH POWER, HIGH-FREQUENCY CONVERTERS IN PARRALLEL OPERATION
By J. H. R. Enslin; J. D. Van Wyk; P. Van Rhyn; J. J. Schoeman [View]
[Download]

Abstract: A 30 kVA high-frequency link converter, which consists of 6x5 kVA center-tap power block topologies operating in parallel, is considered for battery-fed dc-ac converter applications. Practical solutions on minimizing circulating currents between the different power blocks, avoiding transformer saturation in forced commutated center-tap topologies and minimizing transistor on-losses are incorporated and illustrated by means of practical measurements and results. A simple single capacitor snubber network, operating in parallel with a second stage capacitor snubber is proposed for these converter types. Typical applications include mobile and telecommunications uninterruptable power supply (UPS) systems, high ac-voltage loads fed from photovoltaic or hybrid energy systems and battery-fed mobile variable speed ac and dc drives.

EPE 1987 - 05 - Lecture Session 1.05: CONVERTERS (I)
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1987 - Conference > EPE 1987 - 05 - Lecture Session 1.05: CONVERTERS (I)
	[return to parent folder]

	DIRECT DIGITAL CONTROL OF FOUR-QUADRANT POWER CONVERTER By T. Seger; M. Wächter	[View] [Download]
Abstract: BBC has equipped eight four axle multi-purpose main-line locomotives Re 4/4 with asynchronous induction motor drives fed by voltage source inverters. Input power conversion is achieved by means of a Four-Quadrant Power Converter. Both the inverter and the converter are equipped with GTO's and fully controlled by four micro-controllers. Two of them are closely linked and handle the control algorithms of the Four-Quadrant Power Converter. One uP is for line synchronization and voltage control, the second uP handles all current control tasks and PWM of the three secondary loops. Design objectives were a good power factor ( = 1) and fast dynamic response. The extended possibilities of the MICAS(R) automation system allow the implementation of better control technology and the integration of extended diagnostic capability during normal operation of the drive system. As a result, the first two locomotives show good dynamic behaviour and very low harmonic content in the line current.

	THE DESIGN OF A HIGH STABILITY (10 PPM) BI-POLAR 700W CONTINUOUSLY VARIABLE OUTPUT SWITCHED MODE POWER CONVERTER By R. Forrest; C. D. M. Oates	[View] [Download]
Abstract: CERN, the European Centre for Particle Physics Research, had a requirement for a large number of converters to power corrector magnets for LEP (Large Electron Positron Collider) which is under construction at Geneva. The work was done in collaboration with GEC Transmission and Distribution Projects Limited, who designed the power converter and voltage control, following a technical specification issued by CERN. The precision current control capable of 10 ppm stability on the 5 Amp output was designed by CERN. Various design aspects are discussed, including the design of the power circuit, the PWM control, filtering and the servo control loops. Particular consideration is given to aspects of SMPS which have prevented them being used in high precision requirements until now, ie loop stability versus bandwidth, ripple filtering and RFI emission and susceptibility.

	THE EVOLUTION OF UPS-SYSTEMS OVER VARIOUS GENERATIONS AND THEIR FURTHER DEVELOPMENT By H. E. Schweickardt; H. Beeler	[View] [Download]
Abstract: Today, uninterruptible power supply (UPS) systems have attained a position of ever increasing importance. The present range of UPS equipment permits optimum employment for various applications. This paper shows the development of the UPS from the rotating systems to the standard static equipment of today. Concepts and methods of operation common for today are presented. Progress made on the static UPS equipment since the first generation up to today's designs is illustrated by comparing some of the major features. The most important trends for future equipment developrnent are elucidated.

	DEVELOPMENT AND CHARACTERISTICS OF BATTERY-FED, HIGH POWER, HIGH-FREQUENCY CONVERTERS IN PARRALLEL OPERATION By J. H. R. Enslin; J. D. Van Wyk; P. Van Rhyn; J. J. Schoeman	[View] [Download]
Abstract: A 30 kVA high-frequency link converter, which consists of 6x5 kVA center-tap power block topologies operating in parallel, is considered for battery-fed dc-ac converter applications. Practical solutions on minimizing circulating currents between the different power blocks, avoiding transformer saturation in forced commutated center-tap topologies and minimizing transistor on-losses are incorporated and illustrated by means of practical measurements and results. A simple single capacitor snubber network, operating in parallel with a second stage capacitor snubber is proposed for these converter types. Typical applications include mobile and telecommunications uninterruptable power supply (UPS) systems, high ac-voltage loads fed from photovoltaic or hybrid energy systems and battery-fed mobile variable speed ac and dc drives.