EPE Association: EPE 2019 - LS5c: DC/DC Converters (DCDC)

EPE 2019 - LS5c: DC/DC Converters (DCDC)
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2019 ECCE Europe - Conference > EPE 2019 - Topic 02: Power Converter Topologies and Design > EPE 2019 - LS5c: DC/DC Converters (DCDC)

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   A Multiphase Series-Capacitor Buck Converter with Reduced Flying Capacitor Volume and Auxiliary Start-Up Circuit
By Gianluca ROBERTS [View]
[Download]

Abstract: This paper introduces a modification to the conventional multiphase series-capacitor (SC) buck converter topology that transforms it into a more suitable candidate for emerging high step-down, high current point-of-load (PoL) applications. The introduced topology reduces the total energy storage of the flying capacitors (FC), compared to an equivalently-phase conventional SC topology, as a result of lowering their respective steady-state voltages. This translates into easier procurement of capacitors and greater than 33\% smaller FC volume due to lower capacitive derating. The converter also includes an unobtrusive auxiliary switch to facilitate the pre-charging of each FC to near their steady-state voltage such that the critical high current-carrying synchronous rectifiers (SR) never experience a voltage stress equal to the supply voltage. This advantageous property subsequently enables the designer to safely use lower voltage / higher figure-of-merit (FoM) SRs to boost operating efficiency. An interleaved 4-phase discrete prototype was developed for 48-V nominal input and 1.0-1.8-V output at 140-A load to confirm diminished SR voltage stress during startup-up that ultimately improves efficiency at heavy-load.

   A Non-Regulated Full-Bridge Resonant Converter for Implementing CC and CV Charging strategies of Electric Vehicles
By Nam VU [View]
[Download]

Abstract: This paper introduces a new converter for implementing CC and CV charging strategies for battery electric vehicles by using an isolated full-bridge converter with adding a variable-resonant tank. Thanks to the variable-resonant tank, the proposed converter is able to implement CC and CV control strategies with a fixed-switching frequency and not using any regulation for the primary switches. This capability of non-regulation is achievable due to inherent characteristics (constant-current frequency and constant-voltage frequency) of the variable-resonant tank. Since the proposed converter only operates at these resonant frequencies, it can achieve the ZVS and ZCS for all semiconductor devices. A design optimization framework is used to design the resonant tanks to properly achieve all advantages. To verify the improved performances, a software simulation of 3.3 kW was conducted. The results have shown that the proposed converter can charge the battery with a constant current of 7.8 A, a constant voltage of 420 V at a fixed frequency of 50 kHz.

   An isolated bidirectional half-bridge active-clamp current-fed push-pull DC-DC converter for DC microgrid applications
By Matthias SCHULZ [View]
[Download]

Abstract: This paper describes an isolated bidirectional half-bridge active-clamp current-fed push-pull DC/DC converter developed for a DC microgrid. A novel modulation scheme is introduced for step-down operation, which decreases the switching losses mainly on the higher voltage side of the converter. Also, the effect on step-up operation mode is analyzed in detail. A prototype of the converter is built with a nominal output power of 600 W exhibiting a peak efficiency of 96.8\% in step-down operation. Measurements show a good agreement with the simulated key waveforms. The topology has also a highly efficient step-up operation mode with a peak effi-ciency of 96.2\%.

   DC-DC High Step-up Converter with Low Count of Switches Based on Resonant Switched-Capacitor Topology
By Robert STALA [View]
[Download]

Abstract: This paper presents the research results of a novel DC-DC boost converter with high voltage gain, low count of switches and low voltage stresses on the switches. The operation of the converter is based on the principle of a switched-capacitor voltage multiplier (SCVM) but the utilization of the components is very effective in the proposed idea, because the converter is able to charge two output capacitors with only one additional switch and a diode. An important benefit of the proposed converter is that the gate circuits do not require isolated supply and all the switches utilize bootstrap supply. The converter can be designed with air-based or planar PCB-type chokes. Therefore, it can achieve low weight, low volume, decreased cost and simplified assembling. The voltage stress on two switches is close to only half of the output voltage. The stresses on the other switches are much lower, which is very favorable. The converter can be designed in various switch technologies. In a design without ferrite cores and with WBG switches, the converter can operate at higher temperatures.

EPE 2019 - LS5c: DC/DC Converters (DCDC)
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2019 ECCE Europe - Conference > EPE 2019 - Topic 02: Power Converter Topologies and Design > EPE 2019 - LS5c: DC/DC Converters (DCDC)
	[return to parent folder]

	A Multiphase Series-Capacitor Buck Converter with Reduced Flying Capacitor Volume and Auxiliary Start-Up Circuit By Gianluca ROBERTS	[View] [Download]
Abstract: This paper introduces a modification to the conventional multiphase series-capacitor (SC) buck converter topology that transforms it into a more suitable candidate for emerging high step-down, high current point-of-load (PoL) applications. The introduced topology reduces the total energy storage of the flying capacitors (FC), compared to an equivalently-phase conventional SC topology, as a result of lowering their respective steady-state voltages. This translates into easier procurement of capacitors and greater than 33\% smaller FC volume due to lower capacitive derating. The converter also includes an unobtrusive auxiliary switch to facilitate the pre-charging of each FC to near their steady-state voltage such that the critical high current-carrying synchronous rectifiers (SR) never experience a voltage stress equal to the supply voltage. This advantageous property subsequently enables the designer to safely use lower voltage / higher figure-of-merit (FoM) SRs to boost operating efficiency. An interleaved 4-phase discrete prototype was developed for 48-V nominal input and 1.0-1.8-V output at 140-A load to confirm diminished SR voltage stress during startup-up that ultimately improves efficiency at heavy-load.

	A Non-Regulated Full-Bridge Resonant Converter for Implementing CC and CV Charging strategies of Electric Vehicles By Nam VU	[View] [Download]
Abstract: This paper introduces a new converter for implementing CC and CV charging strategies for battery electric vehicles by using an isolated full-bridge converter with adding a variable-resonant tank. Thanks to the variable-resonant tank, the proposed converter is able to implement CC and CV control strategies with a fixed-switching frequency and not using any regulation for the primary switches. This capability of non-regulation is achievable due to inherent characteristics (constant-current frequency and constant-voltage frequency) of the variable-resonant tank. Since the proposed converter only operates at these resonant frequencies, it can achieve the ZVS and ZCS for all semiconductor devices. A design optimization framework is used to design the resonant tanks to properly achieve all advantages. To verify the improved performances, a software simulation of 3.3 kW was conducted. The results have shown that the proposed converter can charge the battery with a constant current of 7.8 A, a constant voltage of 420 V at a fixed frequency of 50 kHz.

	An isolated bidirectional half-bridge active-clamp current-fed push-pull DC-DC converter for DC microgrid applications By Matthias SCHULZ	[View] [Download]
Abstract: This paper describes an isolated bidirectional half-bridge active-clamp current-fed push-pull DC/DC converter developed for a DC microgrid. A novel modulation scheme is introduced for step-down operation, which decreases the switching losses mainly on the higher voltage side of the converter. Also, the effect on step-up operation mode is analyzed in detail. A prototype of the converter is built with a nominal output power of 600 W exhibiting a peak efficiency of 96.8\% in step-down operation. Measurements show a good agreement with the simulated key waveforms. The topology has also a highly efficient step-up operation mode with a peak effi-ciency of 96.2\%.

	DC-DC High Step-up Converter with Low Count of Switches Based on Resonant Switched-Capacitor Topology By Robert STALA	[View] [Download]
Abstract: This paper presents the research results of a novel DC-DC boost converter with high voltage gain, low count of switches and low voltage stresses on the switches. The operation of the converter is based on the principle of a switched-capacitor voltage multiplier (SCVM) but the utilization of the components is very effective in the proposed idea, because the converter is able to charge two output capacitors with only one additional switch and a diode. An important benefit of the proposed converter is that the gate circuits do not require isolated supply and all the switches utilize bootstrap supply. The converter can be designed with air-based or planar PCB-type chokes. Therefore, it can achieve low weight, low volume, decreased cost and simplified assembling. The voltage stress on two switches is close to only half of the output voltage. The stresses on the other switches are much lower, which is very favorable. The converter can be designed in various switch technologies. In a design without ferrite cores and with WBG switches, the converter can operate at higher temperatures.