EPE Association: EPE 2020 - LS1a: High Frequency Power Converters

EPE 2020 - LS1a: High Frequency Power Converters
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2020 ECCE Europe - Conference > EPE 2020 - Topic 02: Power Converter Topologies and Design > EPE 2020 - LS1a: High Frequency Power Converters

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   Bidirectional Isolated Ripple Cancel Triple Active Bridge DC-DC Converter
By Takahiro OHTA [View]
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Abstract: To achieve a highly reliable DC distribution microgrid network, a bidirectional isolated ripple cancel triple active bridge (TAB) converter is proposed in this paper. In a conventional full-bridge TAB converter, the DC-link capacitors suffer from high ripple current, which significantly reduces their lifetime. To solve this issue, the proposed converter can reduce the ripple current to nearly zero by adding the clamping capacitors as an internal ripple-cancellation circuit topology. In addition, the proposed converter inherits the advantages of the conventional full-bridge TAB converter such as a wide range of soft switching and bidirectional power conversion. This makes it easier to replace the conventional full-bridge TAB converters. Finally, a 1 kW prototype was built to demonstrate its feasibility. In the experiment, the ripple current reduced to nearly zero (0.16 A) under 400 V/400 V/400 V and rated power 1 kW operating conditions. The proposed converter could be used to make highly reliable and efficient DC distribution microgrid as a power router.

   Dual Interleaved 3.6 kW LLC Converter Operating in Half-Bridge, Full-Bridge and Phase-Shift Mode as a Single-Stage Architecture of an Automotive On-Board DC-DC
By Philipp REHLAENDER [View]
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Abstract: On-board DC-DC converters are required to operate over a wide input and output voltage range depending on the state-of-charge of the input and output battery. Conventionally, the power transfer between these batteries is enabled by a two-stage converter concept where a galvanically-coupled DC-DC converter regulates the input voltage of the second-stage galvanically-isolated DC-DC converter. This paper presents a single-stage interleaved 3.6 kW LLC converter for this purpose. While LLC converters are usually not suitable for such a wide voltage range, this LLC converter is operated in full-bridge mode for large gains and in half-bridge mode for low gains. For intermediate gains and loads, the LLC makes use of phase-shift mode. To operate the interleaved LLCs at an equal switching frequency enabling output current ripple cancellation, again phase-shift mode is utilized to balance the output currents during full-bridge mode while asymmetrical duty-cycle mode is proposed for current balancing during half-bridge mode. This paper analyzes the converter design for these modes of operation. A 3.6 kW-prototype employing Si-superjunction MOSFETs achieves a power density of 2.1 kW/l. The maximum efficiency reaches 96.5 \% while for most operating points it is kept well above 90 \%.

   Implementation of Control Strategy for Step-down DC-DC Converter Based on Piezoelectric Resonator
By Mustapha TOUHAMI [View]
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Abstract: With the growth in demand for miniaturization in power electronics, the current solutions are starting to display their limits in dimensions, power densities and efficiency. To meet the previous demands, the new piezoelectric materials achieving high power densities and efficiency could be the solution to ensuring the requirements. The piezoelectric resonators (PRs) and the piezoelectric transformers (PTs) have been used previously. Unlike the PTs, the use of PRs in power electronics has not been fully explored, and their use has been limited by emulating switched capacitors. A new operating principle using PRs based on energy and electrical balance exhibits good performances in steady state. In this paper, our motivation is to investigate in the capability to control a dc-dc converter based on PRs using this operating principle. Indeed, this paper presents the control strategy of a new step-down DC-DC converter based on a piezoelectric resonator (PR), which is used as an energy storage element. The operating principle of the converter is also presented. Moreover, the control algorithm has been implemented in field programmable gate array (FPGA) to regulate the output voltage. The control principle is validated experimentally for input-output voltages 120 - 48 V, and achieving an efficiency up to 94\% for large operating points.

EPE 2020 - LS1a: High Frequency Power Converters
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2020 ECCE Europe - Conference > EPE 2020 - Topic 02: Power Converter Topologies and Design > EPE 2020 - LS1a: High Frequency Power Converters
	[return to parent folder]

	Bidirectional Isolated Ripple Cancel Triple Active Bridge DC-DC Converter By Takahiro OHTA	[View] [Download]
Abstract: To achieve a highly reliable DC distribution microgrid network, a bidirectional isolated ripple cancel triple active bridge (TAB) converter is proposed in this paper. In a conventional full-bridge TAB converter, the DC-link capacitors suffer from high ripple current, which significantly reduces their lifetime. To solve this issue, the proposed converter can reduce the ripple current to nearly zero by adding the clamping capacitors as an internal ripple-cancellation circuit topology. In addition, the proposed converter inherits the advantages of the conventional full-bridge TAB converter such as a wide range of soft switching and bidirectional power conversion. This makes it easier to replace the conventional full-bridge TAB converters. Finally, a 1 kW prototype was built to demonstrate its feasibility. In the experiment, the ripple current reduced to nearly zero (0.16 A) under 400 V/400 V/400 V and rated power 1 kW operating conditions. The proposed converter could be used to make highly reliable and efficient DC distribution microgrid as a power router.

	Dual Interleaved 3.6 kW LLC Converter Operating in Half-Bridge, Full-Bridge and Phase-Shift Mode as a Single-Stage Architecture of an Automotive On-Board DC-DC By Philipp REHLAENDER	[View] [Download]
Abstract: On-board DC-DC converters are required to operate over a wide input and output voltage range depending on the state-of-charge of the input and output battery. Conventionally, the power transfer between these batteries is enabled by a two-stage converter concept where a galvanically-coupled DC-DC converter regulates the input voltage of the second-stage galvanically-isolated DC-DC converter. This paper presents a single-stage interleaved 3.6 kW LLC converter for this purpose. While LLC converters are usually not suitable for such a wide voltage range, this LLC converter is operated in full-bridge mode for large gains and in half-bridge mode for low gains. For intermediate gains and loads, the LLC makes use of phase-shift mode. To operate the interleaved LLCs at an equal switching frequency enabling output current ripple cancellation, again phase-shift mode is utilized to balance the output currents during full-bridge mode while asymmetrical duty-cycle mode is proposed for current balancing during half-bridge mode. This paper analyzes the converter design for these modes of operation. A 3.6 kW-prototype employing Si-superjunction MOSFETs achieves a power density of 2.1 kW/l. The maximum efficiency reaches 96.5 \% while for most operating points it is kept well above 90 \%.

	Implementation of Control Strategy for Step-down DC-DC Converter Based on Piezoelectric Resonator By Mustapha TOUHAMI	[View] [Download]
Abstract: With the growth in demand for miniaturization in power electronics, the current solutions are starting to display their limits in dimensions, power densities and efficiency. To meet the previous demands, the new piezoelectric materials achieving high power densities and efficiency could be the solution to ensuring the requirements. The piezoelectric resonators (PRs) and the piezoelectric transformers (PTs) have been used previously. Unlike the PTs, the use of PRs in power electronics has not been fully explored, and their use has been limited by emulating switched capacitors. A new operating principle using PRs based on energy and electrical balance exhibits good performances in steady state. In this paper, our motivation is to investigate in the capability to control a dc-dc converter based on PRs using this operating principle. Indeed, this paper presents the control strategy of a new step-down DC-DC converter based on a piezoelectric resonator (PR), which is used as an energy storage element. The operating principle of the converter is also presented. Moreover, the control algorithm has been implemented in field programmable gate array (FPGA) to regulate the output voltage. The control principle is validated experimentally for input-output voltages 120 - 48 V, and achieving an efficiency up to 94\% for large operating points.