EPE Association: EPE 2003 - Topic 08b: DC Power Supplies (Hard & Soft Switching)

EPE 2003 - Topic 08b: DC Power Supplies (Hard & Soft Switching)
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2003 - Conference > EPE 2003 - Topic 08: POWER SUPPLIES > EPE 2003 - Topic 08b: DC Power Supplies (Hard & Soft Switching)

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   DC power supplies for a fusion plasma experimental facility
By H. Chikaraishi; S. Takami; T. Inoue; S. Sakakibara; S. Imagawa; R. Kumazawa; Y. Takeiri; K. Matsuoka; T. Ise; D. Etou; H. Niwa; T. Haga [View]
[Download]

Abstract: The LHD is a fusion experimental facility using a large scale superconducting coil system. The coil system includes six sets of superconducting coils, and six DC power supplies are used to charge them. For the current controllers of these power supplies, high accuacy of current control, fast response and robustness of system are required. This paper describes the current control system for the LHD DC power supplies. First, the outline of the power system is presented, and then, the current controllers for the LHD are described. Finally, experimental results are presented and discussed in case of coil excitation using these control systems. the results show the various characteristics for each control system and indicated it possible to control the system according to the requirements from a plasma experiment.

   Evaluation of maximum power point tracking control based on I-V curve normalized equation for photovoltaic solar energy conversion
By S. Tadakuma; K. Azuma; Y. Okunushi; A. Akdag [View]
[Download]

Abstract: The paper describes a maximum power tracking technique applied to the control system for photovoltaic power generation via formulating the I-V characteristics. The control performance is estimated by comparing the actual values with the estimated I-V curves. The maximum power operating point is mathematically obtained from the approximate expression. This system is evaluated enough to be of practical use.

   Operation and design of a half-bridge converter incorporating half-turns by emulation
By K.D. Papastergiou; D.E. Macpherson; B. Lees [View]
[Download]

Abstract: The paper investigates an unexplored technique emulating fractional turns in the secondary of a transformer. The emulation of fractional turns can be applied in a half bridge topology in order to improve the output voltage regulation and lead to a more efficient and compact transformer. the technique is demonstrated through an example and the operational characteristics are analysed. It is shown that, in particular cases, the proposed technique can be an invaluable tool.

   600V versus 800V conventional and charge compensated MOSFETs in flyback converters
By H. Kapels; M. Pürschel; I. Zverev [View]
[Download]

Abstract: This paper demonstrates the advantages of 800V MOSFETs in quasi-resonant flyback converters compared to hard switching circuits with 600V or 800V devices. Moreover, using the characteristics of modern compensation power MOSFETs, the flyback efficiency can further be improved.

   Low power high voltage DC-DC converters based on a PZT transformer
By J.-M. Jarrousse; F. Costa; D. Vasic; E. Sarraute [View]
[Download]

Abstract: This paper presents a DC-DC converter insulated by a piezoelectric transformer (PT) [1][2] automatically controlled at its mechanical resonance frequency by a Phase Locked Loop (PLL). This converter is intended for the micro-systems supply requiring less than one watt and a few ten or hundred volt. Several supply structures have been studied. We will depict the selected structure and its driving principle.

   Analysis and design of a new phase shift full bridge converter with series-connected two transformers
By G.-B. Koo; T.-S. Kim; G.-W. Moon; M.-J. Youn [View]
[Download]

Abstract: A new phase shift full bridge (PSFB) converter with series-connected two transformers is proposed in this paper. The proposed converter features wide ZVS ranges and no output inductor is needed due to the series-connected two transformers. The mode analysis including ZVS operation principles compared to a conventional PSFB converter, large signal modeling, and design equations are presented. Experimental results verify that the proposed converter can achieve a significant improvement in the efficiency for a 100W (5V, 20A) telecommunication on-board power supply.

   Design and implementation of phase-shifted parallel-input/series-output dual converter
By C.-W. Roh; J.-il Kang; S.-S. Lee; G.-W. Moon; C.-W. Hong; M.-J. Youn [View]
[Download]

Abstract: The phase-shifted parallel-input/series-output dual converter for high-performance high-power dc/dc step-up applications has been proposed. After a brief review of the proposed converter, the detailed design guidelines, the hardware realization, and the experimental results are presented.

   Soft switching DC-DC boost converter for automotive applications
By F. Gustin; H. Gualous; A. Berthon [View]
[Download]

Abstract: The purpose of such an application is to boost energy stored in batteries or ultracapacitors at variable low voltages to feed a common DC bus at about 42V for automotive embedded applications. The range of power for these applications will be up to some kW (nominal power at 4 kW). In this direct proposed conversion topology, transistors MOSFET operate under soft switching conditions that is to say that this converter will present very low losses. Another advantage will be presented with the HF link intermediate bus, which permits the adaptation of voltage levels thanks to new planar technology for transformers. Test bench has been developed to valid this structure, different tests are presented but are limited by output current (20A).

   Optimal interleaving of DC-DC converters in automotive applications
By M. Gerber; J. A. Ferreira; I. W. Hofsajer; N. Seliger [View]
[Download]

Abstract: Power electronics is finding more and more applications in the automotive environment. Many of these applications are implemented in the engine compartment imposing significant requirements on the electrical, thermal and volumetric performance of the power electronics. One such example is the DC/DC converter required in the new 42V powernet [1,2]. In this paper, interleaving is considered as a means to improve the performance of the DC/DC converter by reducing the filtering component requirements and losses in the generally large filter capacitors. Generic equations are derived that quantify the RMS and peak to peak currents in the filter capacitors as a function of the number of phases. It is also shown that the choice of the inductance is more important than originally anticipated in minimizing the RMS current in the capacitors. The generic equations offer a very efficient way to gain insight into the performance and to improve the performance of an interleaved system. The derived equations are experimentally verified.

   Efficient pulsed high-voltage power supply
By J.-P. Karst [View]
[Download]

Abstract: High-voltage power supply topologies which rapidly charge and discharge a capacitive load are discussed. With increasing voltage and charge/discharge frequency the total power dissipation of the circuit is of increasing importance. A bidirectional stacked flyback converter is proposed to minimise power dissipation and part count. An optimisation strategy is presented to achieve both fast transient voltage rise- and fall times and high efficiency. A 3-stack 3kV prototype based on a planar transformer design is presented.

   Design considerations of resonant transition forward converter with actiove clamp
By V. Tuomainen; J. Kyyrä [View]
[Download]

Abstract: Forward converter with active clamp is a suitable topology for a low output voltage and high output current DC-DC power supply module. The topology can be used in a resonant transition manner to obtain a low voltage over the main switch at turn-on instant. A low voltage, or even zero voltage, is obtainable by adjusting the magnitude of the magnetizing current of the transformer and the delay between the two primary side switches. An increased magnetizing current, however, increases conduction losses in the primary side of the converter and may consume the advantage gained in the switching losses. The converter can also be easily used for self-driven synchronous rectification. However, the aim for low switching losses for the primary side switch may deteriorate performance of the self-driven synchronous rectifiers, particularly at high loads. This paper presents a study of the use of the resonant transition in Forward with active clamp and self-driven synchronous rectifiers. The emphasis is on the comparison of the achieved efficiency with different voltage levels over the primary switch prior to turning it on. Measurement results show that, at low loads, a reduced voltage level improves the efficiency but, on the other hand, at high loads the advantage is not so significant, or it may be totally lost, mainly due to the increased losses of the self-driven synchronous rectifiers. The paper includes discussion on the effect of the magnetizing inductance on the efficiency of the converter and the optimal voltage level at which the primary switch should be turned on. Measurement results from a 3.4 V, 30 A prototype converter are included.

   The imput impedance of a Buck converter
By K. Kostov; J. Kyyrä; T. Suntio [View]
[Download]

Abstract: Dc-dc switch mode power converters (SMPCs) appear as negative input impedance for the dc power line. This can cause instability and therefore it is worth studying how converter’s input impedance depends on various factors. This paper studies in detail the input impedance of a buck converter operating in continuous conduction mode (CCM) by using converter’s state-space average (SSA) model. Three different PWM control schemes are considered – the voltage-mode control (VMC), input voltage feedforward (IVFF) and peak current mode control (PCMC). Results show, that for a given operating point, the input impedance depends on converter’s control. According to the theory a step down converter with IVFF has input impedance, which is a pure negative resistance regardless of converter’s regulation bandwidth, i.e. within the entire frequency range, where the SSA model is valid. The same applies for a PCMC buck converter, if optimal slope compensation is used. The input impedance of a VMC step-down converter is a second order transfer function, which is approximately negative real number only in the lowest frequency range of the control bandwidth.

EPE 2003 - Topic 08b: DC Power Supplies (Hard & Soft Switching)
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2003 - Conference > EPE 2003 - Topic 08: POWER SUPPLIES > EPE 2003 - Topic 08b: DC Power Supplies (Hard & Soft Switching)
	[return to parent folder]

	DC power supplies for a fusion plasma experimental facility By H. Chikaraishi; S. Takami; T. Inoue; S. Sakakibara; S. Imagawa; R. Kumazawa; Y. Takeiri; K. Matsuoka; T. Ise; D. Etou; H. Niwa; T. Haga	[View] [Download]
Abstract: The LHD is a fusion experimental facility using a large scale superconducting coil system. The coil system includes six sets of superconducting coils, and six DC power supplies are used to charge them. For the current controllers of these power supplies, high accuacy of current control, fast response and robustness of system are required. This paper describes the current control system for the LHD DC power supplies. First, the outline of the power system is presented, and then, the current controllers for the LHD are described. Finally, experimental results are presented and discussed in case of coil excitation using these control systems. the results show the various characteristics for each control system and indicated it possible to control the system according to the requirements from a plasma experiment.

	Evaluation of maximum power point tracking control based on I-V curve normalized equation for photovoltaic solar energy conversion By S. Tadakuma; K. Azuma; Y. Okunushi; A. Akdag	[View] [Download]
Abstract: The paper describes a maximum power tracking technique applied to the control system for photovoltaic power generation via formulating the I-V characteristics. The control performance is estimated by comparing the actual values with the estimated I-V curves. The maximum power operating point is mathematically obtained from the approximate expression. This system is evaluated enough to be of practical use.

	Operation and design of a half-bridge converter incorporating half-turns by emulation By K.D. Papastergiou; D.E. Macpherson; B. Lees	[View] [Download]
Abstract: The paper investigates an unexplored technique emulating fractional turns in the secondary of a transformer. The emulation of fractional turns can be applied in a half bridge topology in order to improve the output voltage regulation and lead to a more efficient and compact transformer. the technique is demonstrated through an example and the operational characteristics are analysed. It is shown that, in particular cases, the proposed technique can be an invaluable tool.

	600V versus 800V conventional and charge compensated MOSFETs in flyback converters By H. Kapels; M. Pürschel; I. Zverev	[View] [Download]
Abstract: This paper demonstrates the advantages of 800V MOSFETs in quasi-resonant flyback converters compared to hard switching circuits with 600V or 800V devices. Moreover, using the characteristics of modern compensation power MOSFETs, the flyback efficiency can further be improved.

	Low power high voltage DC-DC converters based on a PZT transformer By J.-M. Jarrousse; F. Costa; D. Vasic; E. Sarraute	[View] [Download]
Abstract: This paper presents a DC-DC converter insulated by a piezoelectric transformer (PT) [1][2] automatically controlled at its mechanical resonance frequency by a Phase Locked Loop (PLL). This converter is intended for the micro-systems supply requiring less than one watt and a few ten or hundred volt. Several supply structures have been studied. We will depict the selected structure and its driving principle.

	Analysis and design of a new phase shift full bridge converter with series-connected two transformers By G.-B. Koo; T.-S. Kim; G.-W. Moon; M.-J. Youn	[View] [Download]
Abstract: A new phase shift full bridge (PSFB) converter with series-connected two transformers is proposed in this paper. The proposed converter features wide ZVS ranges and no output inductor is needed due to the series-connected two transformers. The mode analysis including ZVS operation principles compared to a conventional PSFB converter, large signal modeling, and design equations are presented. Experimental results verify that the proposed converter can achieve a significant improvement in the efficiency for a 100W (5V, 20A) telecommunication on-board power supply.

	Design and implementation of phase-shifted parallel-input/series-output dual converter By C.-W. Roh; J.-il Kang; S.-S. Lee; G.-W. Moon; C.-W. Hong; M.-J. Youn	[View] [Download]
Abstract: The phase-shifted parallel-input/series-output dual converter for high-performance high-power dc/dc step-up applications has been proposed. After a brief review of the proposed converter, the detailed design guidelines, the hardware realization, and the experimental results are presented.

	Soft switching DC-DC boost converter for automotive applications By F. Gustin; H. Gualous; A. Berthon	[View] [Download]
Abstract: The purpose of such an application is to boost energy stored in batteries or ultracapacitors at variable low voltages to feed a common DC bus at about 42V for automotive embedded applications. The range of power for these applications will be up to some kW (nominal power at 4 kW). In this direct proposed conversion topology, transistors MOSFET operate under soft switching conditions that is to say that this converter will present very low losses. Another advantage will be presented with the HF link intermediate bus, which permits the adaptation of voltage levels thanks to new planar technology for transformers. Test bench has been developed to valid this structure, different tests are presented but are limited by output current (20A).

	Optimal interleaving of DC-DC converters in automotive applications By M. Gerber; J. A. Ferreira; I. W. Hofsajer; N. Seliger	[View] [Download]
Abstract: Power electronics is finding more and more applications in the automotive environment. Many of these applications are implemented in the engine compartment imposing significant requirements on the electrical, thermal and volumetric performance of the power electronics. One such example is the DC/DC converter required in the new 42V powernet [1,2]. In this paper, interleaving is considered as a means to improve the performance of the DC/DC converter by reducing the filtering component requirements and losses in the generally large filter capacitors. Generic equations are derived that quantify the RMS and peak to peak currents in the filter capacitors as a function of the number of phases. It is also shown that the choice of the inductance is more important than originally anticipated in minimizing the RMS current in the capacitors. The generic equations offer a very efficient way to gain insight into the performance and to improve the performance of an interleaved system. The derived equations are experimentally verified.

	Efficient pulsed high-voltage power supply By J.-P. Karst	[View] [Download]
Abstract: High-voltage power supply topologies which rapidly charge and discharge a capacitive load are discussed. With increasing voltage and charge/discharge frequency the total power dissipation of the circuit is of increasing importance. A bidirectional stacked flyback converter is proposed to minimise power dissipation and part count. An optimisation strategy is presented to achieve both fast transient voltage rise- and fall times and high efficiency. A 3-stack 3kV prototype based on a planar transformer design is presented.

	Design considerations of resonant transition forward converter with actiove clamp By V. Tuomainen; J. Kyyrä	[View] [Download]
Abstract: Forward converter with active clamp is a suitable topology for a low output voltage and high output current DC-DC power supply module. The topology can be used in a resonant transition manner to obtain a low voltage over the main switch at turn-on instant. A low voltage, or even zero voltage, is obtainable by adjusting the magnitude of the magnetizing current of the transformer and the delay between the two primary side switches. An increased magnetizing current, however, increases conduction losses in the primary side of the converter and may consume the advantage gained in the switching losses. The converter can also be easily used for self-driven synchronous rectification. However, the aim for low switching losses for the primary side switch may deteriorate performance of the self-driven synchronous rectifiers, particularly at high loads. This paper presents a study of the use of the resonant transition in Forward with active clamp and self-driven synchronous rectifiers. The emphasis is on the comparison of the achieved efficiency with different voltage levels over the primary switch prior to turning it on. Measurement results show that, at low loads, a reduced voltage level improves the efficiency but, on the other hand, at high loads the advantage is not so significant, or it may be totally lost, mainly due to the increased losses of the self-driven synchronous rectifiers. The paper includes discussion on the effect of the magnetizing inductance on the efficiency of the converter and the optimal voltage level at which the primary switch should be turned on. Measurement results from a 3.4 V, 30 A prototype converter are included.

	The imput impedance of a Buck converter By K. Kostov; J. Kyyrä; T. Suntio	[View] [Download]
Abstract: Dc-dc switch mode power converters (SMPCs) appear as negative input impedance for the dc power line. This can cause instability and therefore it is worth studying how converter’s input impedance depends on various factors. This paper studies in detail the input impedance of a buck converter operating in continuous conduction mode (CCM) by using converter’s state-space average (SSA) model. Three different PWM control schemes are considered – the voltage-mode control (VMC), input voltage feedforward (IVFF) and peak current mode control (PCMC). Results show, that for a given operating point, the input impedance depends on converter’s control. According to the theory a step down converter with IVFF has input impedance, which is a pure negative resistance regardless of converter’s regulation bandwidth, i.e. within the entire frequency range, where the SSA model is valid. The same applies for a PCMC buck converter, if optimal slope compensation is used. The input impedance of a VMC step-down converter is a second order transfer function, which is approximately negative real number only in the lowest frequency range of the control bandwidth.