EPE Association: EPE 1989 - 24 - Lecture Session 3.7: SWITCHED MODE POWER SUPPLIES

EPE 1989 - 24 - Lecture Session 3.7: SWITCHED MODE POWER SUPPLIES
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   HIGH PERFORMANCES - MEDIUM POWER DC-TO-DC CONVERTER
By F. Forest; Ph. Lienart [View]
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Abstract: Different technics have been developed to improve the power-to-weight ratio of the S.M.P.S., ranging up to few hundred of watts. In order to extend these technics to the 1 to 10kW range, we have designed a 3kW DC to DC converter using resonant switches and providing high efficiency (94%) with a switching frequency of 110kHz. An output characteristics linearization process has been studied to avoid discontinuous conduction mode.

   DC TO DC CONVERTERS WITH BIDIRECTIONAL POWER FLOW AND CONTROLLABLE VOLTAGE RATIO
By H. G. Langer; H.-Ch. Skudelny [View]
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Abstract: DC to dc converters with a high frequency ac link are increasingly used in various applications. If two dc sources are connected through such a converter the transfer ratio of the converter should be controllable in order to counter the load current dependent voltage drops in the sources and the converter. If in addition power transfer is required in both directions a bidirectional, controllable dc to dc converter is necessary. This paper presents the circuit diagram of such a converter. A test circuit capable of a 1-kW power transfer in both directions is described. Test results are shown.

   IMPROVEMENT OF SWITCH-MODE POWER CONVERTERS IN PARALLEL OPERATION
By Alfonso Lago; Carlos M. Penalver [View]
[Download]

Abstract: A good efficiency converter, which consists of several Swich-Mode Power Converters operating in parallel has been developed. Practical solutions to minimize circulating currents between single converters, auxiliary control circuits for to share the output load demands equally among each SMPC's and a widely study about the operation modes between converters ( asynchronous and synchronous mode ), with the relationships between efficiency and the associated disadvantages of paralleled converters, are described and illustrated by means of practical measurements and results. Typical applications include mobile and telecommunications uninterruptible power supply systems, loads with high power requirements or high power switching supply customers.

   HARMONIC DISTORTION OF THE MAINS VOLTAGE BY SWITCHED-MODE POWER SUPPLIES - ASSESSMENT OF THE FUTURE DEVELOPMENT AND POSSIBLE MITIGATION MEASURES
By R. Gretsch; W. Gunselmann [View]
[Download]

Abstract: The growing use of power supplies for electronic equipment increases the amount of harmonic voltages in the mains system mainly caused by small rectifiers with capacitive smoothing. Assessments show that in the future during times of low-load, this rectifier type could come up to half the residential load in public LV-systems causing a highly distorted mains voltage which doesn't meet the compatibility level. Therefore, more strict harmonic emission limits for these rectifier type are proposed by a new IEC-draft: it's basic philosophy is explained. Some methods to mitigate the harmonic current emission of these circuits and, thus, to meet the new requirements are introduced: by "mixing" different types of passive rectifier circuits and especially controlled switched-mode power supplies, an efficient reduction of the harmonic distortion seems to be possible.

EPE 1989 - 24 - Lecture Session 3.7: SWITCHED MODE POWER SUPPLIES
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1989 - Conference > EPE 1989 - 24 - Lecture Session 3.7: SWITCHED MODE POWER SUPPLIES
	[return to parent folder]

	HIGH PERFORMANCES - MEDIUM POWER DC-TO-DC CONVERTER By F. Forest; Ph. Lienart	[View] [Download]
Abstract: Different technics have been developed to improve the power-to-weight ratio of the S.M.P.S., ranging up to few hundred of watts. In order to extend these technics to the 1 to 10kW range, we have designed a 3kW DC to DC converter using resonant switches and providing high efficiency (94%) with a switching frequency of 110kHz. An output characteristics linearization process has been studied to avoid discontinuous conduction mode.

	DC TO DC CONVERTERS WITH BIDIRECTIONAL POWER FLOW AND CONTROLLABLE VOLTAGE RATIO By H. G. Langer; H.-Ch. Skudelny	[View] [Download]
Abstract: DC to dc converters with a high frequency ac link are increasingly used in various applications. If two dc sources are connected through such a converter the transfer ratio of the converter should be controllable in order to counter the load current dependent voltage drops in the sources and the converter. If in addition power transfer is required in both directions a bidirectional, controllable dc to dc converter is necessary. This paper presents the circuit diagram of such a converter. A test circuit capable of a 1-kW power transfer in both directions is described. Test results are shown.

	IMPROVEMENT OF SWITCH-MODE POWER CONVERTERS IN PARALLEL OPERATION By Alfonso Lago; Carlos M. Penalver	[View] [Download]
Abstract: A good efficiency converter, which consists of several Swich-Mode Power Converters operating in parallel has been developed. Practical solutions to minimize circulating currents between single converters, auxiliary control circuits for to share the output load demands equally among each SMPC's and a widely study about the operation modes between converters ( asynchronous and synchronous mode ), with the relationships between efficiency and the associated disadvantages of paralleled converters, are described and illustrated by means of practical measurements and results. Typical applications include mobile and telecommunications uninterruptible power supply systems, loads with high power requirements or high power switching supply customers.

	HARMONIC DISTORTION OF THE MAINS VOLTAGE BY SWITCHED-MODE POWER SUPPLIES - ASSESSMENT OF THE FUTURE DEVELOPMENT AND POSSIBLE MITIGATION MEASURES By R. Gretsch; W. Gunselmann	[View] [Download]
Abstract: The growing use of power supplies for electronic equipment increases the amount of harmonic voltages in the mains system mainly caused by small rectifiers with capacitive smoothing. Assessments show that in the future during times of low-load, this rectifier type could come up to half the residential load in public LV-systems causing a highly distorted mains voltage which doesn't meet the compatibility level. Therefore, more strict harmonic emission limits for these rectifier type are proposed by a new IEC-draft: it's basic philosophy is explained. Some methods to mitigate the harmonic current emission of these circuits and, thus, to meet the new requirements are introduced: by "mixing" different types of passive rectifier circuits and especially controlled switched-mode power supplies, an efficient reduction of the harmonic distortion seems to be possible.