EPE Association: EPE 1989 - 14 - Lecture Session 2.7: SWITCHED MODE POWER SUPPLIES

EPE 1989 - 14 - Lecture Session 2.7: SWITCHED MODE POWER SUPPLIES
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1989 - Conference > EPE 1989 - 14 - Lecture Session 2.7: SWITCHED MODE POWER SUPPLIES

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   COMPARISON OF SWITCHES LOSSES BETWEEN FORCED COMMUTATION CONVERTER AND RESONANT CONVERTER
By J. Roudet; J. P. Keradec; T. Rafesthain [View]
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Abstract: This article is aimed to make both a theoretical and experimental comparison between two kinds of DC-DC energy converters. We study a forced commutation converter and a resonant series converter which can work both thyristor mode and thyristor dual mode. The experimental study consists of an evaluation of the switching and conduction losses for each semi-conductor . For each structure we study the influence of the technology: Bipolar and IGBT. In order to do that we put into practice a measuring equipment of instantaneous power which makes it possible to visualize the power during commutation as well as the way of point of operation. The results of these measurements should allow a better choice of structure and technology for a given converter.

   INSTABILITY PHENOMENON IN RESONANT CONVERTERS
By M. Brunello; J. P. Ferrieux; E. Toutain; Ch. Masselot [View]
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Abstract: In this paper, authors present and examine a major problem for resonant converters instability. The first part provides an overview of the operation and the various control modes of a current reversible, series, resonant DC-DC converter. Then, after defining a simplified equivalent diagram for resonant converters, the instability phenomenon is analyzed in detail, using two actual converter examples. Simulation and experiments are used to represent the problem. Finally, using the equivalent diagram defined, a phenomenon analysis is performed for both control modes described in part one.

   USE OF RESONANT DEVICES IN UNINTERRUPTIBLE POWER SUPPLIES
By M. Brunello; J. P. Ferrieux; J. Pérard [View]
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Abstract: The purpose of this paper is to show the advantages offered by resonance in uninterruptible power supplies (UPS). The first part reviews the study mode used, along with operating characteristics of a current reversible series DC-DC converter. Then, once the control mode has been selected, dynamic small-signal modeling is performed for this converter using the equivalent medium current generator mode diagram. In the last part, after defining the DC-AC structure, the authors demonstrate the feasibility of resonant DC-AC conversion. Implementation of converter regulation is described and test results are given.

   SERIES-RESONANT SINGLE-PHASE AC-TO-DC POWER SUPPLY WITH ACTIVE POWER FACTOR CONTROL
By J. Ben Klaassens; Marinus P. N. van Wesenbeeck; Hian K. Lauw [View]
[Download]

Abstract: The series-resonant converter is one of the major classes of electronic power converters which is extensively applied for DC-to-DC conversion. This technology transfers bulk energy efficiently through a series-resonant circuit in the direct path of the energy transfer. This resonant converter forms a high-frequency AC-link between the voltage sources connected to the input and output terminals. The high-frequency link is exploited for the application of a modulation process thus avoiding the use of bulky and expensive low-order harmonic filters. The achievable high pulse repetition frequency is rooted in the efficient turn-off mechanism of the semiconductor switches and does not compromise their reliability. The classical objective of an AC-to-DC converter is to control the (average) value of the output waveform (often the output voltage). The energy emanated from the source is adapted by passive filters, often a compromise between volume and effective use. A rectifier-filter network presents a major disadvantage: a power factor less than one. This is caused by distortion of the source current. The resolution of the high-frequency input current of the series-resonant converter introduces the possibility to control the waveform of the source current accurately. In combination with the accurate positioning of the high-frequency current pulses it is possible to influence the exchange of power with the source by the introduced method of active filtering. A power factor equal to one will lead to an optimal operation. However the zero-crossing of the AC source voltage introduces the necessity to store energy. Bulky low-frequency storage elements will increase the specific volume and weight of the converter while the exchange of energy with storage elements will decrease the overall efficiency. The energy stored in the resonant circuit is fundamentally too low to solve this problem. The stored energy in the output capacitor necessary to decrease the high-frequency ripple voltage is available for these purposes. To obtain the optimal conditions for the source-sided power factor a bipolar flow of energy has to be implemented.

EPE 1989 - 14 - Lecture Session 2.7: SWITCHED MODE POWER SUPPLIES
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1989 - Conference > EPE 1989 - 14 - Lecture Session 2.7: SWITCHED MODE POWER SUPPLIES
	[return to parent folder]

	COMPARISON OF SWITCHES LOSSES BETWEEN FORCED COMMUTATION CONVERTER AND RESONANT CONVERTER By J. Roudet; J. P. Keradec; T. Rafesthain	[View] [Download]
Abstract: This article is aimed to make both a theoretical and experimental comparison between two kinds of DC-DC energy converters. We study a forced commutation converter and a resonant series converter which can work both thyristor mode and thyristor dual mode. The experimental study consists of an evaluation of the switching and conduction losses for each semi-conductor . For each structure we study the influence of the technology: Bipolar and IGBT. In order to do that we put into practice a measuring equipment of instantaneous power which makes it possible to visualize the power during commutation as well as the way of point of operation. The results of these measurements should allow a better choice of structure and technology for a given converter.

	INSTABILITY PHENOMENON IN RESONANT CONVERTERS By M. Brunello; J. P. Ferrieux; E. Toutain; Ch. Masselot	[View] [Download]
Abstract: In this paper, authors present and examine a major problem for resonant converters instability. The first part provides an overview of the operation and the various control modes of a current reversible, series, resonant DC-DC converter. Then, after defining a simplified equivalent diagram for resonant converters, the instability phenomenon is analyzed in detail, using two actual converter examples. Simulation and experiments are used to represent the problem. Finally, using the equivalent diagram defined, a phenomenon analysis is performed for both control modes described in part one.

	USE OF RESONANT DEVICES IN UNINTERRUPTIBLE POWER SUPPLIES By M. Brunello; J. P. Ferrieux; J. Pérard	[View] [Download]
Abstract: The purpose of this paper is to show the advantages offered by resonance in uninterruptible power supplies (UPS). The first part reviews the study mode used, along with operating characteristics of a current reversible series DC-DC converter. Then, once the control mode has been selected, dynamic small-signal modeling is performed for this converter using the equivalent medium current generator mode diagram. In the last part, after defining the DC-AC structure, the authors demonstrate the feasibility of resonant DC-AC conversion. Implementation of converter regulation is described and test results are given.

	SERIES-RESONANT SINGLE-PHASE AC-TO-DC POWER SUPPLY WITH ACTIVE POWER FACTOR CONTROL By J. Ben Klaassens; Marinus P. N. van Wesenbeeck; Hian K. Lauw	[View] [Download]
Abstract: The series-resonant converter is one of the major classes of electronic power converters which is extensively applied for DC-to-DC conversion. This technology transfers bulk energy efficiently through a series-resonant circuit in the direct path of the energy transfer. This resonant converter forms a high-frequency AC-link between the voltage sources connected to the input and output terminals. The high-frequency link is exploited for the application of a modulation process thus avoiding the use of bulky and expensive low-order harmonic filters. The achievable high pulse repetition frequency is rooted in the efficient turn-off mechanism of the semiconductor switches and does not compromise their reliability. The classical objective of an AC-to-DC converter is to control the (average) value of the output waveform (often the output voltage). The energy emanated from the source is adapted by passive filters, often a compromise between volume and effective use. A rectifier-filter network presents a major disadvantage: a power factor less than one. This is caused by distortion of the source current. The resolution of the high-frequency input current of the series-resonant converter introduces the possibility to control the waveform of the source current accurately. In combination with the accurate positioning of the high-frequency current pulses it is possible to influence the exchange of power with the source by the introduced method of active filtering. A power factor equal to one will lead to an optimal operation. However the zero-crossing of the AC source voltage introduces the necessity to store energy. Bulky low-frequency storage elements will increase the specific volume and weight of the converter while the exchange of energy with storage elements will decrease the overall efficiency. The energy stored in the resonant circuit is fundamentally too low to solve this problem. The stored energy in the output capacitor necessary to decrease the high-frequency ripple voltage is available for these purposes. To obtain the optimal conditions for the source-sided power factor a bipolar flow of energy has to be implemented.