EPE Association: NORpie 2000 - Topic 11: SWITCH MODE CONVERTERS

NORpie 2000 - Topic 11: SWITCH MODE CONVERTERS
You are here: EPE Documents > 05 - EPE Supported Conference Proceedings > NORpie - Proceedings > NORpie 2000 > NORpie 2000 - Topic 11: SWITCH MODE CONVERTERS

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   DYNAMIC MODELING OF A PEAK-CURRENT-MODE CONTROLLED FORWARD CONVERTER IN CICM
By T. Suntio; J. Lempinen; I. Gadoura; K. Zenger [View]
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Abstract: This paper will present the procedure of small-signal modeling of a peak-current-mode controlled Forward converter in continuous inductor-current mode. The effect of transformer isolation on the dynamic performance is of special interest. It has been noticed in practice that the transformer isolation has significant effect on the dynamic behavior but is not fully understood or modeled earlier. This effect can be modeled in a similar manner as the effect of artificial compensation ramp but adding also the dynamics of input voltage. This will change significantly the duty-cycle constraints and consequently the dynamic behavior.

   Effects of Nonperiodic and Chaotic Switching on the Conducted EMI Emissions of Switch Mode Power Supplies
By Mikko Kuisma; Pertti Silventoinen; Tero Järveläinen; Tony Vesterinen [View]
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Abstract: Switch mode power supplies (SMPS) that have a periodic switching pattern have an EMI spectrum that contains switching frequency and its harmonic frequencies with significant amplitude at least up to 21st harmonic. Two methods to reduce the harmonic frequencies basing on the spread spectrum technology are presented in this paper. First method is based on hysteresis control and the other one utilizes chaotic phenomena. Some answers to question “Is the spread spectrum switching a method to decrease EMI emissions or just a way to bluff the measurement devices?” are presented.

   High-Current Low-Voltage Power Supply for Particle Accelerators
By V. Grigore; V. Tuomainen; J. Kyyrä; P. Korhonen; R. Turunen [View]
[Download]

Abstract: The paper presents the development of a high-current and low-voltage (2kA/8V) power supply, for superconducting magnets used in particle accelerators. This special application requires high efficiency and reliability, paralleling capability, very low output voltage ripple (<10mV), very good dynamic response, small volume and low weight. The power supply has a modular construction based on the full-bridge topology. The paper describes design issues for this special application and presents the obtained performance.

   CONTROL ENGINEERING METHODS IN ANALYSIS AND DESIGN OF DC/DC CONVERTERS
By K. Zenger; I. Gadoura; T. Suntio [View]
[Download]

Abstract: General control engineering methods are used to study controller design and analysis methods of DC/DC converters. The buck converter is studied as an example, and special emphasis is given to nonidealities modelled by equivalent series resistors (ESRs). In the case of a constant power load the open loop system is shown to be stable even with small resistor values of the ESRs; this result is confirmed by simulations. Based on the small signal model of the converter, a lead-lag compensator is designed by using frequency domain techniques to meet the design specifications. It is shown, how this compensator can with high accuracy be approximated by a PID controller. The operation of the system controlled by the PID controller is then demonstrated by simulations of the closed loop behaviour. The results show a much better performance than those obtained by other tuning methods not considering the ESRs.

NORpie 2000 - Topic 11: SWITCH MODE CONVERTERS
You are here: EPE Documents > 05 - EPE Supported Conference Proceedings > NORpie - Proceedings > NORpie 2000 > NORpie 2000 - Topic 11: SWITCH MODE CONVERTERS
	[return to parent folder]

	DYNAMIC MODELING OF A PEAK-CURRENT-MODE CONTROLLED FORWARD CONVERTER IN CICM By T. Suntio; J. Lempinen; I. Gadoura; K. Zenger	[View] [Download]
Abstract: This paper will present the procedure of small-signal modeling of a peak-current-mode controlled Forward converter in continuous inductor-current mode. The effect of transformer isolation on the dynamic performance is of special interest. It has been noticed in practice that the transformer isolation has significant effect on the dynamic behavior but is not fully understood or modeled earlier. This effect can be modeled in a similar manner as the effect of artificial compensation ramp but adding also the dynamics of input voltage. This will change significantly the duty-cycle constraints and consequently the dynamic behavior.

	Effects of Nonperiodic and Chaotic Switching on the Conducted EMI Emissions of Switch Mode Power Supplies By Mikko Kuisma; Pertti Silventoinen; Tero Järveläinen; Tony Vesterinen	[View] [Download]
Abstract: Switch mode power supplies (SMPS) that have a periodic switching pattern have an EMI spectrum that contains switching frequency and its harmonic frequencies with significant amplitude at least up to 21st harmonic. Two methods to reduce the harmonic frequencies basing on the spread spectrum technology are presented in this paper. First method is based on hysteresis control and the other one utilizes chaotic phenomena. Some answers to question “Is the spread spectrum switching a method to decrease EMI emissions or just a way to bluff the measurement devices?” are presented.

	High-Current Low-Voltage Power Supply for Particle Accelerators By V. Grigore; V. Tuomainen; J. Kyyrä; P. Korhonen; R. Turunen	[View] [Download]
Abstract: The paper presents the development of a high-current and low-voltage (2kA/8V) power supply, for superconducting magnets used in particle accelerators. This special application requires high efficiency and reliability, paralleling capability, very low output voltage ripple (<10mV), very good dynamic response, small volume and low weight. The power supply has a modular construction based on the full-bridge topology. The paper describes design issues for this special application and presents the obtained performance.

	CONTROL ENGINEERING METHODS IN ANALYSIS AND DESIGN OF DC/DC CONVERTERS By K. Zenger; I. Gadoura; T. Suntio	[View] [Download]
Abstract: General control engineering methods are used to study controller design and analysis methods of DC/DC converters. The buck converter is studied as an example, and special emphasis is given to nonidealities modelled by equivalent series resistors (ESRs). In the case of a constant power load the open loop system is shown to be stable even with small resistor values of the ESRs; this result is confirmed by simulations. Based on the small signal model of the converter, a lead-lag compensator is designed by using frequency domain techniques to meet the design specifications. It is shown, how this compensator can with high accuracy be approximated by a PID controller. The operation of the system controlled by the PID controller is then demonstrated by simulations of the closed loop behaviour. The results show a much better performance than those obtained by other tuning methods not considering the ESRs.