EPE Association: EPE 2007 - Subtopic 18-2 - DS: Industry specific energy conversion and conditioning technologies

EPE 2007 - Subtopic 18-2 - DS: Industry specific energy conversion and conditioning technologies
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2007 - Conference > EPE 2007 - Topic 18: 'Industry specific energy conversion and conditioning technologies' > EPE 2007 - Subtopic 18-2 - DS: Industry specific energy conversion and conditioning technologies

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   A Novel Class-D Amplifier for Automotive and Public Audition Audio Applications
By FERNANDES E. R.; VINCENZI F. R. S.; FREITAS M. A. A.; GOMES DE FREITAS Luiz; VIEIRA JR. Joao B.; SILVA L. R.; FREITAS L. C. [View]
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Abstract: This paper proposal presents a new high power Class-D audio amplifier for woofer applications. A regulated DC voltage supply is not needed as well as a low pass output filter overcoming the disadvantages of ordinary audio amplifiers structures. A 1kW laboratory prototype was implemented and it was found that a 94\% efficiency and 1\% of THD could be achieved. A detailed design guide line, principle of operation analysis, control strategy, is also included in this paper proposal.

   Analysis and Development of a Ride-through Device for AC Contactors
By BRAGA Marcelo; MILAGRES Thiago; SILVA Sidelmo [View]
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Abstract: Contactors with AC coils are among the most widely utilized electromechanical devices in industry. However, since this kind of equipment is usually very sensitive to disturbances in the utility voltages, they can be responsible for load misoperation and loss of production. This work presents an electronic device to protect AC contactors from power disturbances, such as voltage sags. Using the proposed system, it is possible to keep AC contactors operating continuously, even during voltage sags with residual voltages as low as 10\% of the nominal system voltage or short-term interruptions.

   Analysis Methods and Design of Transformers with Low Leakage Inductance for Pulsed Power Applications
By TEICHERT Christian; LINDEMANN Andreas; DOEBBELIN Reinhard; HERMS Ronny; SCHAETZING Wolfgang [View]
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Abstract: The feasibility to predict the leakage inductance of transformers is important in many power electronic applications. In the paper, approximate calculation methods and a prediction of leakage inductance based on finite elements method (FEM) simulation are considered by the example of pulsed power transformers for capacitor discharge welding arrangements. The effects of the use of transformers with different leakage inductance values on electrical behavior of the circuit, on process parameters and transformer operation in this application are discussed.

   Design and experimental investigation of a magnetically suspended rotary table
By PALIS Frank; SCHALLSCHMIDT Thomas; DRAGANOV Denis [View]
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Abstract: The paper deals with an axial magnetic bearing system for a rotary table. The table is supported by 16 current controlled magnets. Special emphasis is laid on control system design. Here, several control strategies are analyzed and experimentally investigated. High performance of observer based cascade structure control systems is shown

   Design of closed loop audio power amplifiers by means of an accurate model of vented box loudspeakers
By GONZALEZ-ESPIN Fran; GARCERA Gabriel; FIGUERES Emilio; SANDIA Jesus [View]
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Abstract: The purpose of this paper is to analyze the stability of closed loop switching power amplifiers using an accurate model of a loudspeaker installed in a commonly used bass reflex enclosure instead of the purely resistive model that can be used with a Zobel network. The model takes into account the electrical-mechanical-acoustical parameters of the transducer as well as the voice-coil loudspeaker's non-linear behavior, avoiding stability problems when trying to compensate for the output filter stage, thus obtaining better THD figures. This model has been experimentally tested and then used to design a regulator for Voltage-Mode Control method by means of MATLAB software. The regulator has been simulated using a full-bridge power converter along with the proposed model of the transducer.

   Specialized Receivers for Three-Phase Contactless Energy Transfer Desktop Applications
By VANDENPUT Andre; DUARTE Jorge; SONNTAG Christoph; LOMONOVA Elena [View]
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Abstract: In this paper, a new contactless energy transfer (CET) desktop application is presented. The CET desktop uses a matrix of hexagon spiral windings embedded underneath its surface, to transfer power to CET enabled consumer electronics devices placed on the table. To improve efficiency and limit stray magnetic fields, clusters of only three primary coils, located closest to the receiving devices, are excited. The coils are excited with out-of-phase currents to further reduce stray magnetic fields. Due to the design of the CET desktop the power transfer efficiency is not constant but varies throughout the surface of the table. Using the design and evaluation process presented in this paper, different secondary coil configurations can be designed and evaluated to find topologies best suited for different electronic devices. The evaluation process is simulated for two different receiver coil assemblies, and from the results it is shown that receiver coil configurations with multiple small coils have the ability to stabilize the power transfer efficiency in the CET desktop.

   Voltage and Current Ripple Considerations for Improving Ultra-Capacitor Lifetime While Charging with Switch Mode Converters
By GUIDI Giuseppe; UNDELAND Tore; BASU Supratim [View]
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Abstract: Ultra-Capacitors or Supercapacitors that store energy for powering downstream converters used for power conversion need to be charged. When switch mode converters / power supply are used for charging, the significant change in their capacitance with frequency and higher ESR can result in significantly higher voltage ripple in these capacitors. This results in over voltage and temperature rise in these capacitors resulting in their consequent reduction of lifetime. Based on extensive measurements of this charging voltage ripple and charging current ripple at different converter switching frequencies, design considerations that can significantly reduce this voltage and current ripple is proposed in this paper.

EPE 2007 - Subtopic 18-2 - DS: Industry specific energy conversion and conditioning technologies
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2007 - Conference > EPE 2007 - Topic 18: 'Industry specific energy conversion and conditioning technologies' > EPE 2007 - Subtopic 18-2 - DS: Industry specific energy conversion and conditioning technologies
	[return to parent folder]

	A Novel Class-D Amplifier for Automotive and Public Audition Audio Applications By FERNANDES E. R.; VINCENZI F. R. S.; FREITAS M. A. A.; GOMES DE FREITAS Luiz; VIEIRA JR. Joao B.; SILVA L. R.; FREITAS L. C.	[View] [Download]
Abstract: This paper proposal presents a new high power Class-D audio amplifier for woofer applications. A regulated DC voltage supply is not needed as well as a low pass output filter overcoming the disadvantages of ordinary audio amplifiers structures. A 1kW laboratory prototype was implemented and it was found that a 94\% efficiency and 1\% of THD could be achieved. A detailed design guide line, principle of operation analysis, control strategy, is also included in this paper proposal.

	Analysis and Development of a Ride-through Device for AC Contactors By BRAGA Marcelo; MILAGRES Thiago; SILVA Sidelmo	[View] [Download]
Abstract: Contactors with AC coils are among the most widely utilized electromechanical devices in industry. However, since this kind of equipment is usually very sensitive to disturbances in the utility voltages, they can be responsible for load misoperation and loss of production. This work presents an electronic device to protect AC contactors from power disturbances, such as voltage sags. Using the proposed system, it is possible to keep AC contactors operating continuously, even during voltage sags with residual voltages as low as 10\% of the nominal system voltage or short-term interruptions.

	Analysis Methods and Design of Transformers with Low Leakage Inductance for Pulsed Power Applications By TEICHERT Christian; LINDEMANN Andreas; DOEBBELIN Reinhard; HERMS Ronny; SCHAETZING Wolfgang	[View] [Download]
Abstract: The feasibility to predict the leakage inductance of transformers is important in many power electronic applications. In the paper, approximate calculation methods and a prediction of leakage inductance based on finite elements method (FEM) simulation are considered by the example of pulsed power transformers for capacitor discharge welding arrangements. The effects of the use of transformers with different leakage inductance values on electrical behavior of the circuit, on process parameters and transformer operation in this application are discussed.

	Design and experimental investigation of a magnetically suspended rotary table By PALIS Frank; SCHALLSCHMIDT Thomas; DRAGANOV Denis	[View] [Download]
Abstract: The paper deals with an axial magnetic bearing system for a rotary table. The table is supported by 16 current controlled magnets. Special emphasis is laid on control system design. Here, several control strategies are analyzed and experimentally investigated. High performance of observer based cascade structure control systems is shown

	Design of closed loop audio power amplifiers by means of an accurate model of vented box loudspeakers By GONZALEZ-ESPIN Fran; GARCERA Gabriel; FIGUERES Emilio; SANDIA Jesus	[View] [Download]
Abstract: The purpose of this paper is to analyze the stability of closed loop switching power amplifiers using an accurate model of a loudspeaker installed in a commonly used bass reflex enclosure instead of the purely resistive model that can be used with a Zobel network. The model takes into account the electrical-mechanical-acoustical parameters of the transducer as well as the voice-coil loudspeaker's non-linear behavior, avoiding stability problems when trying to compensate for the output filter stage, thus obtaining better THD figures. This model has been experimentally tested and then used to design a regulator for Voltage-Mode Control method by means of MATLAB software. The regulator has been simulated using a full-bridge power converter along with the proposed model of the transducer.

	Specialized Receivers for Three-Phase Contactless Energy Transfer Desktop Applications By VANDENPUT Andre; DUARTE Jorge; SONNTAG Christoph; LOMONOVA Elena	[View] [Download]
Abstract: In this paper, a new contactless energy transfer (CET) desktop application is presented. The CET desktop uses a matrix of hexagon spiral windings embedded underneath its surface, to transfer power to CET enabled consumer electronics devices placed on the table. To improve efficiency and limit stray magnetic fields, clusters of only three primary coils, located closest to the receiving devices, are excited. The coils are excited with out-of-phase currents to further reduce stray magnetic fields. Due to the design of the CET desktop the power transfer efficiency is not constant but varies throughout the surface of the table. Using the design and evaluation process presented in this paper, different secondary coil configurations can be designed and evaluated to find topologies best suited for different electronic devices. The evaluation process is simulated for two different receiver coil assemblies, and from the results it is shown that receiver coil configurations with multiple small coils have the ability to stabilize the power transfer efficiency in the CET desktop.

	Voltage and Current Ripple Considerations for Improving Ultra-Capacitor Lifetime While Charging with Switch Mode Converters By GUIDI Giuseppe; UNDELAND Tore; BASU Supratim	[View] [Download]
Abstract: Ultra-Capacitors or Supercapacitors that store energy for powering downstream converters used for power conversion need to be charged. When switch mode converters / power supply are used for charging, the significant change in their capacitance with frequency and higher ESR can result in significantly higher voltage ripple in these capacitors. This results in over voltage and temperature rise in these capacitors resulting in their consequent reduction of lifetime. Based on extensive measurements of this charging voltage ripple and charging current ripple at different converter switching frequencies, design considerations that can significantly reduce this voltage and current ripple is proposed in this paper.