EPE Association: EPE 2015 - DS2d: Hard & Soft Switching Techniques

EPE 2015 - DS2d: Hard & Soft Switching Techniques
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2015 ECCE Europe - Conference > EPE 2015 - Topic 02: Power Converter Topologies and Design > EPE 2015 - DS2d: Hard & Soft Switching Techniques

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   A NEW ZVT SNUBBER CELL FOR PWM-CCM-PFC BOOST CONVERTERS
By Suat YILDIRMAZ [View]
[Download]

Abstract: In this study, a new Zero Voltage Transition (ZVT) snubber cell is proposed. Zero Voltage Transition(ZVT) turn on and zero voltage switching (ZVS) turn off are achieved for the main switch. Also, theauxiliary switch is turned on with zero current switching (ZCS) and turned off with ZVS. The mainadvantage of this snubber cell is that it reduces the current stresses of the auxiliary circuit componentssignificantly. The proposed snubber cell, which has been used in Pulse Width Modulated (PWM) -Continues Current Modulation (CCM) - Power Factor Correction (PFC) boost converter, has beenverified both by simulation software and experimentally.

   A Novel ZCS Back-to-Back Current Source Converter for High Power Applications
By Dipankar DE [View]
[Download]

Abstract: This paper focuses a novel Zero Current Switched (ZCS) back-to-back current source converter for high power applications. A single DC link auxiliary circuit with a new commutation scheme helps to achieve soft switching for rectifier, inverter side and auxiliary switches. Two different switching algorithm (namely, Type-I and Type-II) are proposed depending upon the relative switching instants of rectifier and inverter side devices. Type-II switching algorithm helps to reduce effective switching frequency of auxiliary circuit and maintains improved pulse accuracy over type-I switching counter-part. Design and analysis of the power circuit for 2MVA/4160V system, simulation results from a back-to-back current source converter are presented.

   Comparison study of Half-Bridge LCC and LLC Resonant DC-DC Converter with Wide Output Range
By Saijun MAO [View]
[Download]

Abstract: The Half-Bridge (HB) LCC resonant DC-DC converter and HB LLC resonant DC-DC converter circuit are comparatively studied for high efficiency ultra-wide output power range application in this paper. The output voltage ranges from minimum output voltage to twice that value. And the output current ranges from 10\% load to 100\% load. So the output power spans over a wide range, from minimum to 20 times that. The detailed resonant tank characteristics analysis for HB LCC and LLC resonant converter is provided. Through the 150W hard prototype experiments validation, it is shown that HB LLC resonant DC-DC converter can achieve better performance with flat efficiency, narrow switching frequency range compared with HB LCC resonant DC-DC converter for wide output current application at both 75V & 150V output voltage from 10\% output current to 100 \% output current conditions. HB LLC resonant DC-DC converter is more preferred power conversion circuit topology to achieve high performance with flat efficiency, narrow switching frequency range in ultra-wide output power range applications.

   Complete Analytical Formulae of Inverter Power Loss under Infrequent Switching Condition
By Kimihisa FURUKAWA [View]
[Download]

Abstract: Analytical methods of power semiconductor loss in a two-level inverter conventionally assume a sufficient number of switching pulses per electrical fundamental cycle. This paper presents a complete analytical expression of power loss even under an infrequent switching condition. The proposed formula is demonstrated with several PWM topologies.

   Design Considerations of 1 MHz LLC Resonant Converter with GaN E-HEMT
By Hwapyeong PARK [View]
[Download]

Abstract: LLC resonant converters with high switching frequency can show high power density by reducing thesize of passive components, such as the output capacitor and transformer. However, it is difficult tooperate the PWM generator and at a high switching frequency. Moreover, soft start operation requiresmuch higher switching frequency than the nominal one. Therefore, this paper proposes a new soft startalgorithm to suppress high inrush current with limited switching frequency. In addition, stableoperation of the LLC converter at the high switching frequency is considered. GaN E-HEMTs areselected to achieve the high switching frequency operation due to its small drain-source resistance andsmall parasitic capacitance. However, GaN E-HEMTs also have different switching operationcharacteristics t. In this paper, the design and implementation of a 1 MHz LLC resonant converter areproposed to verify the improvement of power density reducing the passive component size. The softstart algorithm for high switching frequency is analyzed for small inrush currents at the cold startcondition. Simulation and implementation are used to verify the validity of the soft start algorithm.The side effects of high switching frequency operation are analyzed to design the power componentsand PCB. The high speed switching characteristics of the GaN E-HEMT are also analyzed to obtainproper operation for a half-bridge type LLC resonant converter using a boostrap circuit. Simulationand experimental results are presented to show the validity of the proposed analysis and designmethods with a 1 MHz prototype converter using GaN E-HEMTs.

   Experimental evaluation of SiC BJT and SiC MOSFET in a series resonant converter.
By Georg TOLSTOY [View]
[Download]

Abstract: SiC devices such as MOSFETs and BJTs have proven themselves to be contenders to improve the efficiency of resonant converters. The losses of the full-bridge inverter are well below 1\% of the rated power at switching frequencies up to 200 kHz, making it possible to reach even higher frequencies. An experimental setup is built and two different full-bridge inverters are tested. One is built with SiC MOSFETs and no additional anti-parallel diodes and one with SiC BJTs and SiC Schottky diodes.

   Minimization of Leakage Ground Current in Transformerless Single-Phase Full-Bridge Photovoltaic Inverters
By EFTICHIOS KOUTROULIS [View]
[Download]

Abstract: The market of PV systems is rapidly expanding during the last years and the transformerless DC/AC inverters are key components in this evolution. Despite its design and control simplicity, atransformerless full-bridge DC/AC inverter may exhibit a high leakage ground current, due tocapacitive coupling between the solar panels and ground, which prohibits its employment insingle-phase PV systems. Thus, multiple alternative transformerless PV inverter topologies have beendeveloped in the past, which, however, comprise additional power devices and/or passive components.In this paper, a new modulation method is proposed for optimally controlling the power switches oftransformerless single-phase full-bridge PV inverters, such that their leakage ground current isminimized. The design results demonstrate that by using the proposed technique, the leakage groundcurrent of transformerless full-bridge inverters is reduced below the maximum limit imposed by theVDE 0126-1-1 standard, thus enabling their application in single-phase PV installations, instead ofmore complex PV inverter structures.

   MODIFIED CURRENT PULSE CHARGING METHOD FOR LEAD-ACID BATTERIES BASED ON PHASE-SHIFT FULL-BRIDGE CONVERTER IN UPS'S FAMILY APPLICATIONS
By RENATO CARDOSO [View]
[Download]

Abstract: This paper describes a modified current pulse charging method for lead-acid batteries applied to a familyof Uninterruptable Power Supplies with a bank of sealed lead-acid batteries (VRLA). The proposedmethod is presented based on a phase-shift Full-Bridge converter with galvanic isolation. Experimentalresults are presented to validate the proposed method.

   Optimal Switching of SiC Lateral MOSFETs
By Erik VELANDER [View]
[Download]

Abstract: The switching loss of the 1700 V SiC Planar-Gate MOSFET is significant at switching frequencies above 2 kHz. If a simple resistive gate driver is adjusted for the worst case operating point (temperature, commutated voltage and current) with a given application dV/dt requirement, other operating points usually have lower dV/dt resulting in non-optimal losses. The paper shows results of an optimized gate-drive solution, adapting a current source control in order to reduce the losses while fulfilling the application dV/dt requirements.

   Optimum Switching States Determination for IGCT Based ANPC Topology
By Ilknur COLAK [View]
[Download]

Abstract: The ANPC topology was developed to overcome the unequal power distribution among the semiconductors in NPC topology. By using an accurate switching model it's possible to adjust the thermal distribution between the semiconductors and increase the output power of the converter. This study focuses on the PWM-3 (fpwm = 350Hz), PWM-5 (fpwm = 550Hz), and PWM-7 (fpwm = 750Hz) and defines the optimum switching sequence for each frequency and specifies the maximum current rating of IGCT based ANPC converter for the mentioned optimum switching sequence.

   SLIDING MODE CONTROL OF PV POWERED DC/DC BUCK-BOOST CONVERTER WITH DIGITAL SIGNAL PROCESSOR
By Mustafa Ergin SAHIN [View]
[Download]

Abstract: In this paper, sliding mode controlled Buck-Boost DC/DC converter powered by Photovoltaic (PV)module for battery charge system is given. The general design of the system is simulated using theMatlab/Simulink software and performed experimentally using Digital Signal Processing (DSP) andnecessary circuits. The sliding mode control is realized based on the inductance current and the outputvoltage of the converter as variables. The performance analysis has been analyzed in detail fordifferent operating conditions of the converter system. The converter has been simulated usingdifferent parameters used for controllers and the PV module. The effects of different parameters havebeen observed with comparison the obtained results. The experimental results are seen similar withsimulation results as expected.

   Switching Losses in a 1.7 kW GaN based Full-Bridge DC-DC Converter with Synchronous Rectification
By RAKESH RAMACHANDRAN [View]
[Download]

Abstract: The paper presents the detailed analysis of switching losses in GaN devices for an isolated full-bridge dc-dc converter. Switching losses includes capacitive losses along with turn-on and turn-off losses of the power MOSFET. In hard switched converters, the output capacitance of MOSFET contributes to a significant part of the switching loss. The capacitive loss analysis also helps in determining the optimum number of devices used in parallel for a given power level and switching frequency. The analysis is performed on a 1.7 kW full bridge isolated dc-dc GaN converter at a switching frequency of 50 kHz. The paper also presents the GaN switch efficiency curve for an isolated dc-dc GaN converter with different number of devices in parallel.

   The Effect of Circuit Parasitics on Resonant Switched Capacitor Converters
By Hassan TAGHIZADEH ESFANJANI [View]
[Download]

Abstract: Switched Capacitor (SC) converters have been used for several years in low-power, powerelectronic energy conversion systems. However, because of their attractive features such aslow-weight and high-density energy conversion and with the emergence of new circuittopologies and SiC switching devices, these circuits have recently been proposed for higherpower applications. The resonant switched capacitor topology is a good candidate for high-powerdue to its very low-switching loss, but circuit parasitic inductance and resistance canhave a significant effect on the resonant frequency of each cell. This paper discusses theinfluence of these parasitics on the performance of the converter and proposes a method bywhich these parasitics can be estimated. Simulation results and measurements from ahardware prototype are used to validate the technique.

EPE 2015 - DS2d: Hard & Soft Switching Techniques
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2015 ECCE Europe - Conference > EPE 2015 - Topic 02: Power Converter Topologies and Design > EPE 2015 - DS2d: Hard & Soft Switching Techniques
	[return to parent folder]

	A NEW ZVT SNUBBER CELL FOR PWM-CCM-PFC BOOST CONVERTERS By Suat YILDIRMAZ	[View] [Download]
Abstract: In this study, a new Zero Voltage Transition (ZVT) snubber cell is proposed. Zero Voltage Transition(ZVT) turn on and zero voltage switching (ZVS) turn off are achieved for the main switch. Also, theauxiliary switch is turned on with zero current switching (ZCS) and turned off with ZVS. The mainadvantage of this snubber cell is that it reduces the current stresses of the auxiliary circuit componentssignificantly. The proposed snubber cell, which has been used in Pulse Width Modulated (PWM) -Continues Current Modulation (CCM) - Power Factor Correction (PFC) boost converter, has beenverified both by simulation software and experimentally.

	A Novel ZCS Back-to-Back Current Source Converter for High Power Applications By Dipankar DE	[View] [Download]
Abstract: This paper focuses a novel Zero Current Switched (ZCS) back-to-back current source converter for high power applications. A single DC link auxiliary circuit with a new commutation scheme helps to achieve soft switching for rectifier, inverter side and auxiliary switches. Two different switching algorithm (namely, Type-I and Type-II) are proposed depending upon the relative switching instants of rectifier and inverter side devices. Type-II switching algorithm helps to reduce effective switching frequency of auxiliary circuit and maintains improved pulse accuracy over type-I switching counter-part. Design and analysis of the power circuit for 2MVA/4160V system, simulation results from a back-to-back current source converter are presented.

	Comparison study of Half-Bridge LCC and LLC Resonant DC-DC Converter with Wide Output Range By Saijun MAO	[View] [Download]
Abstract: The Half-Bridge (HB) LCC resonant DC-DC converter and HB LLC resonant DC-DC converter circuit are comparatively studied for high efficiency ultra-wide output power range application in this paper. The output voltage ranges from minimum output voltage to twice that value. And the output current ranges from 10\% load to 100\% load. So the output power spans over a wide range, from minimum to 20 times that. The detailed resonant tank characteristics analysis for HB LCC and LLC resonant converter is provided. Through the 150W hard prototype experiments validation, it is shown that HB LLC resonant DC-DC converter can achieve better performance with flat efficiency, narrow switching frequency range compared with HB LCC resonant DC-DC converter for wide output current application at both 75V & 150V output voltage from 10\% output current to 100 \% output current conditions. HB LLC resonant DC-DC converter is more preferred power conversion circuit topology to achieve high performance with flat efficiency, narrow switching frequency range in ultra-wide output power range applications.

	Complete Analytical Formulae of Inverter Power Loss under Infrequent Switching Condition By Kimihisa FURUKAWA	[View] [Download]
Abstract: Analytical methods of power semiconductor loss in a two-level inverter conventionally assume a sufficient number of switching pulses per electrical fundamental cycle. This paper presents a complete analytical expression of power loss even under an infrequent switching condition. The proposed formula is demonstrated with several PWM topologies.

	Design Considerations of 1 MHz LLC Resonant Converter with GaN E-HEMT By Hwapyeong PARK	[View] [Download]
Abstract: LLC resonant converters with high switching frequency can show high power density by reducing thesize of passive components, such as the output capacitor and transformer. However, it is difficult tooperate the PWM generator and at a high switching frequency. Moreover, soft start operation requiresmuch higher switching frequency than the nominal one. Therefore, this paper proposes a new soft startalgorithm to suppress high inrush current with limited switching frequency. In addition, stableoperation of the LLC converter at the high switching frequency is considered. GaN E-HEMTs areselected to achieve the high switching frequency operation due to its small drain-source resistance andsmall parasitic capacitance. However, GaN E-HEMTs also have different switching operationcharacteristics t. In this paper, the design and implementation of a 1 MHz LLC resonant converter areproposed to verify the improvement of power density reducing the passive component size. The softstart algorithm for high switching frequency is analyzed for small inrush currents at the cold startcondition. Simulation and implementation are used to verify the validity of the soft start algorithm.The side effects of high switching frequency operation are analyzed to design the power componentsand PCB. The high speed switching characteristics of the GaN E-HEMT are also analyzed to obtainproper operation for a half-bridge type LLC resonant converter using a boostrap circuit. Simulationand experimental results are presented to show the validity of the proposed analysis and designmethods with a 1 MHz prototype converter using GaN E-HEMTs.

	Experimental evaluation of SiC BJT and SiC MOSFET in a series resonant converter. By Georg TOLSTOY	[View] [Download]
Abstract: SiC devices such as MOSFETs and BJTs have proven themselves to be contenders to improve the efficiency of resonant converters. The losses of the full-bridge inverter are well below 1\% of the rated power at switching frequencies up to 200 kHz, making it possible to reach even higher frequencies. An experimental setup is built and two different full-bridge inverters are tested. One is built with SiC MOSFETs and no additional anti-parallel diodes and one with SiC BJTs and SiC Schottky diodes.

	Minimization of Leakage Ground Current in Transformerless Single-Phase Full-Bridge Photovoltaic Inverters By EFTICHIOS KOUTROULIS	[View] [Download]
Abstract: The market of PV systems is rapidly expanding during the last years and the transformerless DC/AC inverters are key components in this evolution. Despite its design and control simplicity, atransformerless full-bridge DC/AC inverter may exhibit a high leakage ground current, due tocapacitive coupling between the solar panels and ground, which prohibits its employment insingle-phase PV systems. Thus, multiple alternative transformerless PV inverter topologies have beendeveloped in the past, which, however, comprise additional power devices and/or passive components.In this paper, a new modulation method is proposed for optimally controlling the power switches oftransformerless single-phase full-bridge PV inverters, such that their leakage ground current isminimized. The design results demonstrate that by using the proposed technique, the leakage groundcurrent of transformerless full-bridge inverters is reduced below the maximum limit imposed by theVDE 0126-1-1 standard, thus enabling their application in single-phase PV installations, instead ofmore complex PV inverter structures.

	MODIFIED CURRENT PULSE CHARGING METHOD FOR LEAD-ACID BATTERIES BASED ON PHASE-SHIFT FULL-BRIDGE CONVERTER IN UPS'S FAMILY APPLICATIONS By RENATO CARDOSO	[View] [Download]
Abstract: This paper describes a modified current pulse charging method for lead-acid batteries applied to a familyof Uninterruptable Power Supplies with a bank of sealed lead-acid batteries (VRLA). The proposedmethod is presented based on a phase-shift Full-Bridge converter with galvanic isolation. Experimentalresults are presented to validate the proposed method.

	Optimal Switching of SiC Lateral MOSFETs By Erik VELANDER	[View] [Download]
Abstract: The switching loss of the 1700 V SiC Planar-Gate MOSFET is significant at switching frequencies above 2 kHz. If a simple resistive gate driver is adjusted for the worst case operating point (temperature, commutated voltage and current) with a given application dV/dt requirement, other operating points usually have lower dV/dt resulting in non-optimal losses. The paper shows results of an optimized gate-drive solution, adapting a current source control in order to reduce the losses while fulfilling the application dV/dt requirements.

	Optimum Switching States Determination for IGCT Based ANPC Topology By Ilknur COLAK	[View] [Download]
Abstract: The ANPC topology was developed to overcome the unequal power distribution among the semiconductors in NPC topology. By using an accurate switching model it's possible to adjust the thermal distribution between the semiconductors and increase the output power of the converter. This study focuses on the PWM-3 (fpwm = 350Hz), PWM-5 (fpwm = 550Hz), and PWM-7 (fpwm = 750Hz) and defines the optimum switching sequence for each frequency and specifies the maximum current rating of IGCT based ANPC converter for the mentioned optimum switching sequence.

	SLIDING MODE CONTROL OF PV POWERED DC/DC BUCK-BOOST CONVERTER WITH DIGITAL SIGNAL PROCESSOR By Mustafa Ergin SAHIN	[View] [Download]
Abstract: In this paper, sliding mode controlled Buck-Boost DC/DC converter powered by Photovoltaic (PV)module for battery charge system is given. The general design of the system is simulated using theMatlab/Simulink software and performed experimentally using Digital Signal Processing (DSP) andnecessary circuits. The sliding mode control is realized based on the inductance current and the outputvoltage of the converter as variables. The performance analysis has been analyzed in detail fordifferent operating conditions of the converter system. The converter has been simulated usingdifferent parameters used for controllers and the PV module. The effects of different parameters havebeen observed with comparison the obtained results. The experimental results are seen similar withsimulation results as expected.

	Switching Losses in a 1.7 kW GaN based Full-Bridge DC-DC Converter with Synchronous Rectification By RAKESH RAMACHANDRAN	[View] [Download]
Abstract: The paper presents the detailed analysis of switching losses in GaN devices for an isolated full-bridge dc-dc converter. Switching losses includes capacitive losses along with turn-on and turn-off losses of the power MOSFET. In hard switched converters, the output capacitance of MOSFET contributes to a significant part of the switching loss. The capacitive loss analysis also helps in determining the optimum number of devices used in parallel for a given power level and switching frequency. The analysis is performed on a 1.7 kW full bridge isolated dc-dc GaN converter at a switching frequency of 50 kHz. The paper also presents the GaN switch efficiency curve for an isolated dc-dc GaN converter with different number of devices in parallel.

	The Effect of Circuit Parasitics on Resonant Switched Capacitor Converters By Hassan TAGHIZADEH ESFANJANI	[View] [Download]
Abstract: Switched Capacitor (SC) converters have been used for several years in low-power, powerelectronic energy conversion systems. However, because of their attractive features such aslow-weight and high-density energy conversion and with the emergence of new circuittopologies and SiC switching devices, these circuits have recently been proposed for higherpower applications. The resonant switched capacitor topology is a good candidate for high-powerdue to its very low-switching loss, but circuit parasitic inductance and resistance canhave a significant effect on the resonant frequency of each cell. This paper discusses theinfluence of these parasitics on the performance of the converter and proposes a method bywhich these parasitics can be estimated. Simulation results and measurements from ahardware prototype are used to validate the technique.