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Gun-woo Moon - One of the best experts on this subject based on the ideXlab platform.

  • an interleaved active clamp forward converter modified for reduced primary Conduction Loss without additional components
    IEEE Transactions on Power Electronics, 2020
    Co-Authors: Yeonho Jeong, Jaedo Park, Gun-woo Moon
    Abstract:

    This paper proposes an interleaved active-clamp forward (IACF) converter modified for high efficiency without any additional component. To employ high input voltage, the components on one active-clamp forward module are re-arranged from the conventional IACF converter. The proposed converter can significantly reduce the primary Conduction Loss with large turns-ratio of the transformer due to the higher input voltage of the modified module and the expanded duty ratio at the nominal input voltage. In addition, unlike the existing approaches, the power density is not affected because there is no additional component. Finally, the proposed converter is validated experimentally using a prototype converter with 36–72 V dc input and 480 W (12 V dc/40 A) output.

  • high efficiency and high power density weinberg converter reducing Conduction Loss and output current ripple for space applications
    Applied Power Electronics Conference, 2019
    Co-Authors: Dongkwan Kim, Yeonho Jeong, Jaeil Baek, Jeongeon Park, Cheolwoo Lim, Gun-woo Moon
    Abstract:

    Weinberg converter is widely used to battery discharge regulator of satellite system because it guarantees soft-switching of all devices and has low output current ripple. However, due to leakage inductance of the coupled inductor and transformer, the voltage stress of powering diode and the output current spike are increased. To overcome these problems, weinberg converter with auxiliary switch and capacitor is presented in this paper. The proposed converter significantly reduces the voltage stress of powering diode. In additions, the output current spike is decreased by adopting auxiliary circuit. Thus, the Conduction Loss of the powering diode and output current ripple are reduced. As a results the proposed converter achieves high efficiency and high power density with the reduced output filter. The verification is performed with 400 W/50 V prototype.

  • a bridgeless dual boost rectifier with soft switching capability and minimized additional Conduction Loss
    IEEE Transactions on Industrial Electronics, 2018
    Co-Authors: Yeonho Jeong, Jaekuk Kim, Gun-woo Moon
    Abstract:

    A bridgeless dual boost rectifier is proposed to achieve a soft switching for power factor correction circuit. Based on the conventional bridgeless dual boost rectifier, an auxiliary circuit is employed in the proposed converter to perform zero-voltage switching of the main switches and zero-current switching of the auxiliary switches. As a result, switching Losses can be significantly reduced. In addition, the design guideline for the optimized turn-on time of the auxiliary switches is presented to minimize the additional Conduction Loss in the auxiliary circuit. The validity of the proposed converter is confirmed by the experimental results of a prototype converter with 100–240 $V_{{\text{AC}}}$ universal-line input and 800-W (400 V/2 A) output.

  • an asymmetric half bridge resonant converter having a reduced Conduction Loss for dc dc power applications with a wide range of low input voltage
    IEEE Transactions on Power Electronics, 2017
    Co-Authors: Yeonho Jeong, Jaekuk Kim, Jaebum Lee, Gun-woo Moon
    Abstract:

    A new asymmetric half-bridge (HB) resonant converter for dc/dc power system with a wide range of low input voltage is proposed in this paper. The proposed converter is easily derived based on the switch integration technique, merging a buck–boost, which is the same with the active-clamp forward's primary circuit, and the HB LLC resonant converter. By adopting the buck–boost circuit in front of the HB LLC resonant converter, higher input voltage of LLC resonant converter stage can be achieved. As a result, the primary Conduction Loss can be significantly reduced. In addition, to cover wide input voltage range, an asymmetric pulse width modulation control is applied. It can mitigate the design limitation for a high efficiency. Moreover, the proposed converter can achieve not only the small Conduction Loss and the optimal design for high efficiency, but also high power density and low cost due to the switch integration technique. The validity of the proposed converter is confirmed by the experimental results of a prototype converter with 36–72 V DC input and 300 W (12 V/25 A) output.

  • half bridge integrated zvs full bridge converter with reduced Conduction Loss for electric vehicle battery chargers
    IEEE Transactions on Industrial Electronics, 2014
    Co-Authors: Iloun Lee, Gun-woo Moon
    Abstract:

    A half-bridge integrated zero-voltage-switching (ZVS) full-bridge converter with reduced Conduction Loss for battery on-board chargers in electric vehicles (EVs) or plug-in hybrid electric vehicles (PHEVs) is proposed in this paper. The proposed converter features a reduction in primary-Conduction Loss and a lower secondary-voltage stress. In addition, the proposed converter has the most favorable characteristics as battery chargers as follows: a full ZVS capability and a significantly reduced output filter size due to the improved output waveform. In this paper, the circuit configuration, operation principle, and relevant analysis results of the proposed converter are described, followed by the experimental results on a prototype converter realized with a scale-downed 2-kW battery charger for EVs or PHEVs. The experimental results validate the theoretical analysis and show the effectiveness of the proposed converter as battery on-board chargers for EVs or PHEVs.

Wilson Eberle - One of the best experts on this subject based on the ideXlab platform.

  • a discontinuous boost power factor correction Conduction Loss model
    European Conference on Cognitive Ergonomics, 2017
    Co-Authors: Wilson Eberle, Fariborz Musavi
    Abstract:

    In this paper, a novel effective duty cycle method is introduced to predict the RMS and average current for power components in discontinuous Conduction mode (DCM) AC-DC boost power factor correction (PFC) topologies. The proposed model can be used for power component Conduction Losses estimation. The RMS current and average current of power components are derived. PSIM simulation and experimental results are used to verify the accuracy of calculation. A DCM boost converter prototype which converts universal AC input voltage to 400 V DC bus was built and tested in order to verify the proposed model. Experimental results demonstrate that the proposed model can be used for accurate estimation of RMS and average currents for the boost PFC topology.

  • a 1 mhz high efficiency 12 v buck voltage regulator with a new current source gate driver
    IEEE Transactions on Power Electronics, 2008
    Co-Authors: Zhiliang Zhang, Wilson Eberle
    Abstract:

    This paper proposes a new current-source gate drive circuit for a synchronous buck converter. The proposed driver can drive two MOSFETs independently with different drive currents for optimal design. For the control MOSFET, the optimal design involves a tradeoff between switching Loss reduction and drive circuit Loss; while for the synchronous-rectifier MOSFET, the optimal design involves a tradeoff between body diode Conduction Loss and drive circuit Loss. Furthermore, the new drive circuit can achieve: 1) significant switching Loss reduction; 2) gate energy recovery and high gate drive voltage to reduce R DS(ON) Conduction Losses; 3) reduced Conduction Loss and reverse recovery Loss of the body diode; and 4) zero-voltage switching of all the drive switches. The improved driver using integrated inductors is presented with multiphase buck voltage regulators (VRs) to reduce the number of magnetic cores and the core Loss. The experimental results prove that a significant efficiency improvement has been achieved. At 1.5-V output, the new driver improves the efficiency from 84% using a conventional driver to 87.3% at 20 A, and at 30 A, from 79.4% to 82.8%. Overall, the new driver approach is attractive from the standpoints of both performance and cost-effectiveness.

  • A new resonant gate-drive circuit with efficient energy recovery and low Conduction Loss
    IEEE Transactions on Industrial Electronics, 2008
    Co-Authors: Wilson Eberle, Yan-fei Liu, P C Sen
    Abstract:

    In this paper, a new resonant gate-drive circuit is proposed to recover a portion of the power-MOSFET-gate energy that is typically dissipated in high-frequency converters. The proposed circuit consists of four control switches and a small resonant inductance. The current through the resonant inductance is discontinuous in order to minimize circulating-current Conduction Loss that is present in other methods. The proposed circuit also achieves quick turn-on and turn-off transition times to reduce switching and Conduction Losses in power MOSFETs. An analysis, a design procedure, and experimental results are presented for the proposed circuit. Experimental results demonstrate that the proposed driver can recover 51% of the gate energy at 5-V gate-drive voltage.

  • A current source gate driver achieving switching Loss savings and gate energy recovery at 1-MHz
    IEEE Transactions on Power Electronics, 2008
    Co-Authors: Wilson Eberle, Yan-fei Liu, Zhijun Zhang, P C Sen
    Abstract:

    In this paper, a new current source gate drive circuit is proposed for power MOSFETs. The proposed circuit achieves quick turn on and turn off transition times to reduce switching Loss and Conduction Loss in power MOSFETs. In addition, it can recover a portion of the CV gate energy normally dissipated in a conventional driver. The circuit consists of four controlled switches and a small inductor (typically 100 nH or less). The current through the inductor is discontinuous in order to minimize circulating current Conduction Loss. This also allows the driver to operate effectively over a wide range of duty cycles with constant peak current-a significant advantage for many applications since turn on and turn off times do not vary with the operating point. Experimental results are presented for the proposed driver operating in a boost converter at 1 MHz, 5 V input, 10 V/5 A output. At 5 V gate drive, a 2.9% efficiency improvement is achieved representing a Loss savings of 24.8% in comparison to a conventional driver.

  • A new resonant gate drive circuit with efficient energy recovery and low Conduction Loss
    31st Annual Conference of IEEE Industrial Electronics Society 2005. IECON 2005., 2005
    Co-Authors: Wilson Eberle, P C Sen, Yan-fei Liu
    Abstract:

    In this paper, a new resonant gate drive circuit is proposed. The proposed circuit consists of four control switches and a small resonant inductance. The current through the resonant inductance is discontinuous in order to minimize circulating current Conduction Loss present in other methods. The proposed circuit also achieves quick turn-on and turn-off transition times to reduce switching Loss and Conduction Loss in power MOSFETS. An analysis, design procedure and simulation results are presented for the proposed circuit

P C Sen - One of the best experts on this subject based on the ideXlab platform.

  • analysis and control of three phase interleaved scc llc resonant converter load sharing considering component tolerance
    European Conference on Cognitive Ergonomics, 2020
    Co-Authors: Bo Sheng, Yan-fei Liu, Xiang Zhou, Wenbo Liu, Yang Chen, P C Sen
    Abstract:

    The Conduction Loss becomes extremely large if applied LLC converter in high power electrical vehicle (EV) applications. Interleaving technique can help reduce the Conduction Loss and expand load capacity for LLC converter. However, component tolerance on resonant tanks causes load sharing problem, leading to severe performance degrading. To solve the problem, Switch-controlled Capacitor (SCC) circuit is added into resonant tanks to offset the component tolerance through reducing equivalent resonant capacitance. The load sharing characteristic of a three-phase LLC converter with and without SCC circuit is analyzed. The proposed control strategy reduces the SCC MOSFET voltage stress. Thus, lower voltage rating MOSFET which usually features of lower turn-on resistance can be used. Phase shedding technique is also performed to improve the light load efficiency. A prototype of a 250V – 430V input, 14V/260A output three-phase SCC-LLC prototype has been built and tested. Experimental results demonstrate the effectiveness of the SCC circuit and the proposed control strategy. Good current sharing performance among three phases is obtained. In addition, a peak efficiency of 96.7% and a full load efficiency of 95.8% are achieved at 380V input.

  • A new resonant gate-drive circuit with efficient energy recovery and low Conduction Loss
    IEEE Transactions on Industrial Electronics, 2008
    Co-Authors: Wilson Eberle, Yan-fei Liu, P C Sen
    Abstract:

    In this paper, a new resonant gate-drive circuit is proposed to recover a portion of the power-MOSFET-gate energy that is typically dissipated in high-frequency converters. The proposed circuit consists of four control switches and a small resonant inductance. The current through the resonant inductance is discontinuous in order to minimize circulating-current Conduction Loss that is present in other methods. The proposed circuit also achieves quick turn-on and turn-off transition times to reduce switching and Conduction Losses in power MOSFETs. An analysis, a design procedure, and experimental results are presented for the proposed circuit. Experimental results demonstrate that the proposed driver can recover 51% of the gate energy at 5-V gate-drive voltage.

  • A current source gate driver achieving switching Loss savings and gate energy recovery at 1-MHz
    IEEE Transactions on Power Electronics, 2008
    Co-Authors: Wilson Eberle, Yan-fei Liu, Zhijun Zhang, P C Sen
    Abstract:

    In this paper, a new current source gate drive circuit is proposed for power MOSFETs. The proposed circuit achieves quick turn on and turn off transition times to reduce switching Loss and Conduction Loss in power MOSFETs. In addition, it can recover a portion of the CV gate energy normally dissipated in a conventional driver. The circuit consists of four controlled switches and a small inductor (typically 100 nH or less). The current through the inductor is discontinuous in order to minimize circulating current Conduction Loss. This also allows the driver to operate effectively over a wide range of duty cycles with constant peak current-a significant advantage for many applications since turn on and turn off times do not vary with the operating point. Experimental results are presented for the proposed driver operating in a boost converter at 1 MHz, 5 V input, 10 V/5 A output. At 5 V gate drive, a 2.9% efficiency improvement is achieved representing a Loss savings of 24.8% in comparison to a conventional driver.

  • A new resonant gate drive circuit with efficient energy recovery and low Conduction Loss
    31st Annual Conference of IEEE Industrial Electronics Society 2005. IECON 2005., 2005
    Co-Authors: Wilson Eberle, P C Sen, Yan-fei Liu
    Abstract:

    In this paper, a new resonant gate drive circuit is proposed. The proposed circuit consists of four control switches and a small resonant inductance. The current through the resonant inductance is discontinuous in order to minimize circulating current Conduction Loss present in other methods. The proposed circuit also achieves quick turn-on and turn-off transition times to reduce switching Loss and Conduction Loss in power MOSFETS. An analysis, design procedure and simulation results are presented for the proposed circuit

Deepak Divan - One of the best experts on this subject based on the ideXlab platform.

  • soft switching solid state transformer with reduced Conduction Loss
    IEEE Transactions on Power Electronics, 2021
    Co-Authors: Liran Zheng, Rajendra Prasad Kandula, Deepak Divan
    Abstract:

    Solid-state transformers (SSTs) are a promising solution photovoltaic (PV), wind, traction, data center, battery energy storage system (BESS), and fast charging electric vehicle (EV) applications. The traditional SSTs are typically three-stage, i.e., hard-switching cascaded multilevel rectifiers and inverters with dual active bridge (DAB) converters, which leads to bulky passives, low efficiency, and high electromagnetic interference (EMI). This article proposes a new soft-switching solid-state transformer (S4T). The S4T has full-range zero-voltage switching (ZVS), electrolytic capacitor-less dc link, and controlled dv/dt , which reduces EMI. The S4T comprises two reverse-blocking current-source inverter (CSI) bridges, auxiliary branches for ZVS, and transformer magnetizing inductor as a reduced dc link with 60% ripple. Compared with the prior S4T, an effective change on the leakage inductance diode is made to reduce the number of the devices on the main power path by 20% for significant Conduction Loss saving and retain the same functionality of damping the resonance between the leakage and resonant capacitors and recycling trapped leakage energy. The Conduction Loss saving is crucial, being the dominating Loss mechanism in SSTs. Importantly, the proposed single-stage SST not only holds the potential for high power density and high efficiency but also has full functionality, e.g., multiport dc loads integration, voltage regulation, and reactive power compensation, unlike the traditional single-stage matrix SST. The S4T can achieve single-stage isolated bidirectional dc–dc, ac–dc, dc–ac, or ac–ac conversion. It can also be configured input-series output-parallel (ISOP) in a modular way for medium-voltage (MV) grids. Hence, the S4T is a promising candidate for the SST. The full functionality, e.g., voltage buck–boost, multiport, etc., and the universality of the S4T for the dc–dc, dc–ac, and ac–ac conversion are verified through the simulations and experiments of two-port and three-port MV prototypes based on 3.3 kV SiC mosfet s in dc–dc, dc–ac, and ac–ac modes at 2 kV.

  • new single stage soft switching solid state transformer with reduced Conduction Loss and minimal auxiliary switch
    Applied Power Electronics Conference, 2020
    Co-Authors: Liran Zheng, Rajendra Prasad Kandula, Deepak Divan
    Abstract:

    This paper presents two new topologies of single-stage soft-switching solid-state transformer. The proposed converters achieve better trade-off than existing solutions between complexity and benefits from auxiliary circuits, which are used for soft switching and to address transformer leakage induced issues. Compared to the state-of-the-art, the proposed converters reduce Conduction Loss by approximately 20% via eliminating or moving the auxiliary diodes from the main power path. Moreover, the proposed converters achieve minimal auxiliary components by using only one auxiliary switch, i.e. >50% auxiliary counts reduction. In fact, the provision eliminates MV auxiliary switches, diodes, and a bulky MV resonant inductor due to impedance scaling law across transformers – significant improvement for MV-to-LV SST application. In addition, the proposed converters inherit the advantages of the soft-switching solid-state transformer, i.e. full load range ZVS capability and low EMI. As such, the proposed low-switch-count converters feature high efficiency, high power density, and low EMI noise. The topologies, design, and operating principles are presented and verified with experimental results at 600 V and 2 kV from two different prototypes.

  • Dynamic DC-Link Current Minimization Control to Improve Current-Source Solid-State Transformer Efficiency
    2020 IEEE Energy Conversion Congress and Exposition (ECCE), 2020
    Co-Authors: Liran Zheng, Xiangyu Han, Rajendra Prasad Kandula, Deepak Divan
    Abstract:

    This paper presents a fast predictive control method to minimize the dc-link current in current-source solid-state transformers (SST). The motivation for dc-link current reduction is to improve efficiency of the SST and reduce Conduction Loss and transformer winding Loss, which are among the major Loss mechanisms of the current source solid-state transformers. The proposed cycle-by-cycle dc-link current minimization strategy is realized by a predictive control method based on the converter model. The dynamic dc-link current reference is calculated each switching cycle by adding up the input and output phase current references with form factors. Therefore, it is adaptive to different loading conditions. Moreover, the control does not require high computational burden and is suitable for implementation in regular DSP for online calculation. In this paper, the improved soft-switching solid-state transformer (S4T) with reduced Conduction Loss is studied as an example of the current-source SST. The dc-link current minimization control method is verified in simulations and experiments at 2 kV under both steady-state and dynamic conditions. With the proposed control, dc-link current can be minimized to achieve approximately 18% Loss reduction of the SST at the operating point under study.

Zhaoming Qian - One of the best experts on this subject based on the ideXlab platform.

  • analysis and optimal design considerations for an improved full bridge zvs dc dc converter with high efficiency
    IEEE Transactions on Power Electronics, 2006
    Co-Authors: Junming Zhang, Xiaogao Xie, Zhaoming Qian
    Abstract:

    This paper proposes an improved full bridge dc-dc converter, which can achieve zero-voltage-switching (ZVS) with wide input voltage range and load range. The operation principle of the converter and the optimal design considerations for high efficiency and ZVS range are analyzed. By adding two clamp diodes and two small coupled inductors at the primary side of the transformer, the voltage ringing across rectifier diodes is reduced. Therefore, Schottky diodes can be employed to reduce Conduction Loss, and high efficiency is achieved. A 1.2-kW/105-kHz prototype was made with an efficiency higher than 95% at full load to verify the theoretical analysis

  • a novel phase shift controlled zvzcs full bridge dc dc converter analysis and design considerations
    IEEE Industry Applications Society Annual Meeting, 2004
    Co-Authors: Xinke Wu, Chen Zhao, Junming Zhang, Zhaoming Qian
    Abstract:

    A novel ZVZCS full bridge DC-DC converter based on the phase shift control is proposed in this paper. The converter can achieve ZVS for leading lag switches and ZCS for lagging leg switches respectively without any increase both current and voltage stresses. This converter can achieve high efficiency by reducing the circulating Conduction Loss and employing schottky diodes, especially in high input voltage applications. A 1 kW prototype verified the theoretical analysis.