EPE Association: EPE 2016 - LS2e: Contactless Power Supplies

EPE 2016 - LS2e: Contactless Power Supplies
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2016 ECCE Europe - Conference > EPE 2016 - Topic 07: Power Supplies > EPE 2016 - LS2e: Contactless Power Supplies

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   Comprehensive Design Approach for a Two-Stage Fixed-Frequency Contactless Energy Transfer System Based on the Extended First Harmonic Approximation
By Alexander BUCHER [View]
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Abstract: Resonant converters represent a suitable family of topologies that can handle the loose inductive coupling encountered in applications for contactless energy transfer while still providing high efficient operation. However, the analysis of resonant converters is in general cumbersome. On circuit level, a design procedure based on the extended first harmonic approximation of the mul-ti-resonant LLCC converter with secondary side series compensation is presented in this paper. Together with a numerical model for the field distribution of core geometries with rotational symmetry a combined design procedure is discussed for the resonant tank. A high number of design parameters is included in this approach regarding the winding layout of the transmission coils such as number of turns, number of strands and strand diameter of the litz wire, also taking into account the high frequency losses of the windings. The resulting two-stage system with the resonant converter working on a fixed-frequency was designed to be very tolerant against varia-tions of the distance between the coils, at the same time achieving a very high efficiency for this kind of application.

   Consideration on Efficiency Characteristics to Switching Frequency of Secondary-side Converter with Inductive Power Transfer System for Electric Vehicle
By Ryosuke OTA [View]
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Abstract: A battery charger applying an inductive power transfer (IPT) for electric vehicles has various advantages. Then, there is a case that the secondary-side converter is connected to the receiving side of the IPT system in order to regulate the charging power for the battery of electric vehicles. In the previous studies about this converter, it was investigated that the type of the secondary-side converter affects the efficiency of the resonant circuit. However, the optimal switching frequency of the secondary-side converter is not investigated although the optimal converter type and operation mode are investigated in the previous studies. It is possible that the secondary-side converter achieves even higher efficiency by optimally controlling the switching frequency of the converter because the switching frequency affects the converter efficiency. Therefore, this paper investigates the efficiency characteristics of the switching frequency of the secondary-side converter by the theoretical analysis and experimental results in order to establish a high efficient control scheme which controls the switching frequency of the converter. As a result, it is observed that there are similar tendencies in the efficiency characteristics between the results of the theoretical analysis and experimental results. In addition, this paper shows an operation guideline of the secondary-side converter obtaining high efficiency by controlling the switching frequency of the converter.

   Externally-fed auxiliary power supply of MMC converter cells
By Bernhard WUNSCH [View]
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Abstract: We designed an auxiliary power supply for medium voltage MMC-converters with system voltages up to 36 kV\_rms. The system supplies up to 250 W power and is based on a two-stage design. The first stage is an inductive power transfer system that isolates against the system voltage. It is connected to a low voltage DC-supply on ground potential, and shows DC-DC efficiency between 90-95\%. Two distinct insulation concepts for the coupled coil design have been designed and passed partial discharge tests. The second stage supplies the various gate and control units of each MMC power cell. Its insulation requirement is given by the cell voltage. Functional and insulation tests as well as a sensitivity analysis are included. The full auxiliary power supply shows an efficiency of 86\%.

   Theoretical Analysis and Experiments for Higher Efficiency of Coaxial Contactless Power Transmission and Demonstration of minimodel for Electric Railways
By Yoshiyuki YAMAGUCHI [View]
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Abstract: A novel contactless power supply system for electric trains is proposed based on structure of an air gapped coaxial transformer. Theoretical analysis, simulation results and verification experiments were conducted and the results are shown in this paper. The 96.9 \% efficiency at about 200 W was observed with an air gap (2.5 mm) coaxial structure. It was conducted that traction power was delivered by coaxial contactless power transmission. The verification of possibility of power transmission while moving are conducted.

EPE 2016 - LS2e: Contactless Power Supplies
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2016 ECCE Europe - Conference > EPE 2016 - Topic 07: Power Supplies > EPE 2016 - LS2e: Contactless Power Supplies
	[return to parent folder]

	Comprehensive Design Approach for a Two-Stage Fixed-Frequency Contactless Energy Transfer System Based on the Extended First Harmonic Approximation By Alexander BUCHER	[View] [Download]
Abstract: Resonant converters represent a suitable family of topologies that can handle the loose inductive coupling encountered in applications for contactless energy transfer while still providing high efficient operation. However, the analysis of resonant converters is in general cumbersome. On circuit level, a design procedure based on the extended first harmonic approximation of the mul-ti-resonant LLCC converter with secondary side series compensation is presented in this paper. Together with a numerical model for the field distribution of core geometries with rotational symmetry a combined design procedure is discussed for the resonant tank. A high number of design parameters is included in this approach regarding the winding layout of the transmission coils such as number of turns, number of strands and strand diameter of the litz wire, also taking into account the high frequency losses of the windings. The resulting two-stage system with the resonant converter working on a fixed-frequency was designed to be very tolerant against varia-tions of the distance between the coils, at the same time achieving a very high efficiency for this kind of application.

	Consideration on Efficiency Characteristics to Switching Frequency of Secondary-side Converter with Inductive Power Transfer System for Electric Vehicle By Ryosuke OTA	[View] [Download]
Abstract: A battery charger applying an inductive power transfer (IPT) for electric vehicles has various advantages. Then, there is a case that the secondary-side converter is connected to the receiving side of the IPT system in order to regulate the charging power for the battery of electric vehicles. In the previous studies about this converter, it was investigated that the type of the secondary-side converter affects the efficiency of the resonant circuit. However, the optimal switching frequency of the secondary-side converter is not investigated although the optimal converter type and operation mode are investigated in the previous studies. It is possible that the secondary-side converter achieves even higher efficiency by optimally controlling the switching frequency of the converter because the switching frequency affects the converter efficiency. Therefore, this paper investigates the efficiency characteristics of the switching frequency of the secondary-side converter by the theoretical analysis and experimental results in order to establish a high efficient control scheme which controls the switching frequency of the converter. As a result, it is observed that there are similar tendencies in the efficiency characteristics between the results of the theoretical analysis and experimental results. In addition, this paper shows an operation guideline of the secondary-side converter obtaining high efficiency by controlling the switching frequency of the converter.

	Externally-fed auxiliary power supply of MMC converter cells By Bernhard WUNSCH	[View] [Download]
Abstract: We designed an auxiliary power supply for medium voltage MMC-converters with system voltages up to 36 kV\_rms. The system supplies up to 250 W power and is based on a two-stage design. The first stage is an inductive power transfer system that isolates against the system voltage. It is connected to a low voltage DC-supply on ground potential, and shows DC-DC efficiency between 90-95\%. Two distinct insulation concepts for the coupled coil design have been designed and passed partial discharge tests. The second stage supplies the various gate and control units of each MMC power cell. Its insulation requirement is given by the cell voltage. Functional and insulation tests as well as a sensitivity analysis are included. The full auxiliary power supply shows an efficiency of 86\%.

	Theoretical Analysis and Experiments for Higher Efficiency of Coaxial Contactless Power Transmission and Demonstration of minimodel for Electric Railways By Yoshiyuki YAMAGUCHI	[View] [Download]
Abstract: A novel contactless power supply system for electric trains is proposed based on structure of an air gapped coaxial transformer. Theoretical analysis, simulation results and verification experiments were conducted and the results are shown in this paper. The 96.9 \% efficiency at about 200 W was observed with an air gap (2.5 mm) coaxial structure. It was conducted that traction power was delivered by coaxial contactless power transmission. The verification of possibility of power transmission while moving are conducted.