The Experts below are selected from a list of 2973 Experts worldwide ranked by ideXlab platform

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

  • 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.

  • Estimation of Eddy Current Winding Losses in Soft-Switching Solid-State Transformer
    2019 IEEE Energy Conversion Congress and Exposition (ECCE), 2019
    Co-Authors: Xiwei Zheng, Karthik Kandasamy, Xiangyu Han, Mickael J. Mauger, Prasad Kandula, Deepak Divan
    Abstract:

    The high frequency (HF) Transformer is a critical component of any Solid State Transformer. In the case of soft-switching Solid-State Transformer (S4T), the HF Transformer is similar to a flyback Transformer with the addition of transition stages, resulting in some atypical operating modes. Only one winding is active during the active energy transfer time. However, there is significant proximity effect induced eddy current losses in the inactive winding. During the transition times, both the windings are carrying very HF currents (10-20 times switching frequency) resulting in significant AC copper loss even though the transition period is small (5-10% of switching period). This paper explains the nature of these eddy currents in the open winding and during transitions stages, which are unique to S4T, and presents analysis to evaluate these losses. Mathematical derivations to calculate these unique AC losses are presented. FEM analysis to verify the analytical method is presented.

  • soft switching Solid State Transformer s4t
    IEEE Transactions on Power Electronics, 2018
    Co-Authors: Hao Chen, Deepak Divan
    Abstract:

    This paper presents a new topology for a fully bidirectional soft-switching Solid-State Transformer (S4T). The minimal topology, featuring 12 main devices and a high-frequency Transformer, does not use an intermediate dc voltage link, and provides sinusoidal input and output voltages. The S4T can be configured to interface with two- or multiterminal dc, single- or multiphase ac systems. An auxiliary resonant circuit creates zero-voltage-switching conditions for main devices from no-load to full-load, and helps manage interactions with circuit parasitic elements. The modularized structure allows series and/or parallel stacking of converter cells for high-voltage and high-power applications.

  • Impact of Transformer Leakage Inductance on the Soft-Switching Solid-State Transformer
    2018 IEEE Energy Conversion Congress and Exposition (ECCE), 2018
    Co-Authors: Liran Zheng, Karthik Kandasamy, Rajendra Prasad Kandula, Deepak Divan
    Abstract:

    Leakage inductance is inevitable in high frequency (HF) Transformer design for Solid-State Transformer applications. Managing the energy trapped in leakage is very crucial for a safe and efficient operation of Solid-State Transformer (SST) converters. In the soft-switching Solid-State Transformer (S4T), leakage energy management is achieved in a passive way by having it absorbed in the two auxiliary resonant circuits, one on each side of the HF Transformer. However, this could lead to an additional voltage/current stress on the resonant circuit and could impact various elements of the S4T design. This paper presents a detailed analysis of the resonant circuit operation and analytically derived relations between the leakage inductance and the peak voltage/current stress in the S4T converter. Simulation and experimental results verifying the analysis are presented. Using the derived relations, the design considerations for the S4T resonant circuit parameters are also discussed.

  • Design of a 10-kV·A Soft-Switching Solid-State Transformer (S4T)
    IEEE Transactions on Power Electronics, 2018
    Co-Authors: Hao Chen, Deepak Divan
    Abstract:

    The soft-switching Solid-State Transformer (S4T) employs only 12 main active devices and an auxiliary resonant circuit to implement a bidirectional Solid-State Transformer, with an attractive feature of achieving a full range of zero-voltage-switching conditions for all the main devices. This paper covers detailed design of the power stage, auxiliary resonant circuit, and control of the S4T. The high-frequency Transformer is an essential element for the S4T, and it has a unique feature of dc-biased flux. Design of such a high-frequency Transformer is also discussed in detail in this paper. Soft startup, shutdown, and fast dynamic response under load transients are also attractive behaviors because of the low inertia of the S4T. Experimental results from a 208-V/10-kV·A S4T unit are presented.

Alex Q Huang - One of the best experts on this subject based on the ideXlab platform.

  • 500kVA Hybrid Solid State Transformer (HSST): Design and Implementation of the SST
    2020 IEEE Energy Conversion Congress and Exposition (ECCE), 2020
    Co-Authors: Sanjay Rajendran, Soumik Sen, Liqi Zhang, Zhicheng Guo, Qingyun Huang, Alex Q Huang
    Abstract:

    This paper presents the design and implementation of a Solid-State Transformer (SST) that forms a part of a larger Hybrid Solid State Transformer (HSST). The HSST comprises of a high-power line frequency Transformer (LFT) and a medium voltage SiC SST. The SST is based on a soft-switched dual-active bridge topology. Recently developed 7.2kV/60A SiC Austin SuperMOS devices are used as the medium voltage switches. The predicted SST efficiency at 500VRMS and 125A is 98.01 %, and the net HSST efficiency is estimated at 98.43 % at 500kVA. The MV SST has been tested at power of 10kW and results show a high efficiency of 97%.

  • medium voltage single stage dual active bridge based Solid State Transformer dabsst
    European Conference on Power Electronics and Applications, 2018
    Co-Authors: Soumik Sen, Alex Q Huang, Liqi Zhang, Xin Zhao, Yang Lei, Qianlai Zhu, Xiaoqing Song
    Abstract:

    This paper introduces a single-stage medium voltage (MV) Solid State Transformer (SST) based on dual active bridge topology and recently developed high voltage Super-cascode device. A closed loop control system of the output voltage is designed and verified by simulation results. A fully functional SST based on the proposed concept has been developed and tested with an input voltage of 3.6kV and experimental results show unity power factor operation with zero voltage switching of both primary and secondary devices.

  • Solid State Transformer interfaced pmsg wind energy conversion system
    Applied Power Electronics Conference, 2015
    Co-Authors: Rui Gao, Iqbal Husain, F. Wang, Alex Q Huang
    Abstract:

    The Solid-State Transformer (SST) has been regarded as an emerging technology where emphasis is mainly on the design of the device. To explore its system integration opportunities, this paper proposes and demonstrates a SST interfaced permanent magnet synchronous generator (PMSG) wind energy conversion system. The system integration issues along with wind turbine level control methods have been presented and simulated for power management. Moreover, the lab hardware prototype has been set up, which consists of an induction motor based wind turbine emulator (WTE), PMSG, pulse-width modulation (PWM) rectifier, SST, and resistive load bank. Experiments have been carried out to validate the proposed system and control strategy.

  • Current sensorless power balance strategy for DC/DC converters in a cascaded multilevel converter based Solid State Transformer
    IEEE Transactions on Power Electronics, 2014
    Co-Authors: Xu She, Alex Q Huang, Xijun Ni
    Abstract:

    This letter proposes a current sensorless controller for balancing the power in the dc/dc stage of a cascaded multilevel converter based Solid State Transformer. It is revealed that the equalization of the active power component of duty cycles in the cascaded multilevel rectifier stage can be a good indicator of power balance in the dc/dc stage. Additionally, the power balance of the dc/dc stage can guarantee the voltage balance in the rectifier stage if the differences among the power devices are negligible. Based on this principle, a novel power balance controller without sensing any current in the dc/dc stage is proposed. In the end, experimental results in a seven-level three-stage Solid State Transformer are provided for verifying the proposed method.

  • Power management for DC microgrid enabled by Solid-State Transformer
    IEEE Transactions on Smart Grid, 2014
    Co-Authors: Xunwei Yu, Xiaohu Zhou, Xu She, Alex Q Huang
    Abstract:

    A novel distributed power management scheme is proposed in this paper for a DC microgrid system, which is enabled by Solid-State Transformer (SST). The proposed system includes distributed renewable energy resource (DRER) and distributed energy storage device (DESD). The proposed distributed control algorithm, which only relies on the local information and guarantees full utilization of each module in the system based on their characteristics, is applied to both SST and DC microgrid. To this end, a simulation platform is developed in MATLAB/Simulink, in which Photovoltaic (PV), fuel cell and battery are selected as the typical DRERs and DESD, respectively. Lastly, several typical case studies are carried out and the simulation results verify the proposed distributed power management.

Hao Chen - One of the best experts on this subject based on the ideXlab platform.

  • soft switching Solid State Transformer s4t
    IEEE Transactions on Power Electronics, 2018
    Co-Authors: Hao Chen, Deepak Divan
    Abstract:

    This paper presents a new topology for a fully bidirectional soft-switching Solid-State Transformer (S4T). The minimal topology, featuring 12 main devices and a high-frequency Transformer, does not use an intermediate dc voltage link, and provides sinusoidal input and output voltages. The S4T can be configured to interface with two- or multiterminal dc, single- or multiphase ac systems. An auxiliary resonant circuit creates zero-voltage-switching conditions for main devices from no-load to full-load, and helps manage interactions with circuit parasitic elements. The modularized structure allows series and/or parallel stacking of converter cells for high-voltage and high-power applications.

  • Design of a 10-kV·A Soft-Switching Solid-State Transformer (S4T)
    IEEE Transactions on Power Electronics, 2018
    Co-Authors: Hao Chen, Deepak Divan
    Abstract:

    The soft-switching Solid-State Transformer (S4T) employs only 12 main active devices and an auxiliary resonant circuit to implement a bidirectional Solid-State Transformer, with an attractive feature of achieving a full range of zero-voltage-switching conditions for all the main devices. This paper covers detailed design of the power stage, auxiliary resonant circuit, and control of the S4T. The high-frequency Transformer is an essential element for the S4T, and it has a unique feature of dc-biased flux. Design of such a high-frequency Transformer is also discussed in detail in this paper. Soft startup, shutdown, and fast dynamic response under load transients are also attractive behaviors because of the low inertia of the S4T. Experimental results from a 208-V/10-kV·A S4T unit are presented.

  • High-frequency Transformer design for the soft-switching Solid State Transformer (S4T)
    2017 IEEE Applied Power Electronics Conference and Exposition (APEC), 2017
    Co-Authors: Hao Chen, Deepak Divan
    Abstract:

    High-frequency Transformer is a key element of the Solid State Transformer. The high-frequency Transformer for a patent-pending topology - soft-switching Solid State Transformer (S4T) - has a unique feature of DC biased flux. This paper first evaluates the high-frequency Transformer design using different high-frequency magnetic materials. Then a new hybrid Transformer design methodology, which incorporates magnetic cores and permanent magnets, is also proposed. The permanent magnets provide pre-biased flux for the magnetics such that the usable B-H curve range is extended. Finite element analysis simulation and experimental verification show that the hybrid design can save magnetic materials by more than 50%.

  • a 50 kva three phase Solid State Transformer based on the minimal topology dyna c
    IEEE Transactions on Power Electronics, 2016
    Co-Authors: Hao Chen, Anish Prasai, Rohit Moghe, Kireeti Chintakrinda, Deepak Divan
    Abstract:

    The Dynamic Current or Dyna-C is a minimal topology for implementing the bidirectional three-phase Solid-State Transformer (SST). While only two current-source power conversion stages are employed, the Dyna-C SST has features of voltage step up/down, arbitrary power factors, and frequencies between the input and output terminals. In this paper, a compact 50-kVA three-phase SST based on this minimal topology is designed. More specifically, design considerations and practical implementation techniques are presented. Results from experimental measurements are shown and discussed.

  • dyna c experimental results for a 50 kva 3 phase to 3 phase Solid State Transformer
    Applied Power Electronics Conference, 2014
    Co-Authors: Anish Prasai, Hao Chen, Rohit Moghe, Zbigniew Wolanski, Kireeti Chintakrinda, Aaron Zhou, Juan Carlos Llambes, Deepak Divan
    Abstract:

    A compact, isolated, current-source based bidirectional Solid State Transformer (SST) with configurability for supporting low- or medium-voltage DC and AC application is discussed in this paper. More specifically, design considerations and practical implementation techniques for realizing a 50 kVA 3-phase to 3-phase SST are presented. Results from experimental measurements are shown and discussed.

Iqbal Husain - One of the best experts on this subject based on the ideXlab platform.

  • A PI+passivity-based control of a wind energy conversion system enabled with a Solid-State Transformer
    International Journal of Control, 2020
    Co-Authors: Rafael Cisneros, Rui Gao, Romeo Ortega, Iqbal Husain
    Abstract:

    In this paper, we propose a new control scheme for a wind energy conversion system connected to a Solid-State Transformer-enabled distribution microgrid. The system consists of a wind turbine, a pe...

  • Solid State Transformer interfaced pmsg wind energy conversion system
    Applied Power Electronics Conference, 2015
    Co-Authors: Rui Gao, Iqbal Husain, F. Wang, Alex Q Huang
    Abstract:

    The Solid-State Transformer (SST) has been regarded as an emerging technology where emphasis is mainly on the design of the device. To explore its system integration opportunities, this paper proposes and demonstrates a SST interfaced permanent magnet synchronous generator (PMSG) wind energy conversion system. The system integration issues along with wind turbine level control methods have been presented and simulated for power management. Moreover, the lab hardware prototype has been set up, which consists of an induction motor based wind turbine emulator (WTE), PMSG, pulse-width modulation (PWM) rectifier, SST, and resistive load bank. Experiments have been carried out to validate the proposed system and control strategy.

  • A detailed analytical model of a Solid State Transformer
    2015 IEEE Energy Conversion Congress and Exposition (ECCE), 2015
    Co-Authors: Raja Ayyanar, Iqbal Husain
    Abstract:

    This paper presents a detailed analytical model of the Gen-II Solid State Transformer (SST) being developed at Future Renewable Electric Energy Delivery and Management (FREEDM) Center. This work is a first step to develop control oriented models of SST for supporting system level stability studies and distributed control designs. A complete analytical SST model including power stage and closed loop controls have been derived. The model is useful since it is represented as differential and algebraic equations which can be easily simulated and analyzed. The validity of the model has been verified through time domain simulation and comparison with detailed switching model of SST in Simulink/MATLAB.

Xu She - One of the best experts on this subject based on the ideXlab platform.

  • Power management for DC microgrid enabled by Solid-State Transformer
    IEEE Transactions on Smart Grid, 2014
    Co-Authors: Xunwei Yu, Xiaohu Zhou, Xu She, Alex Q Huang
    Abstract:

    A novel distributed power management scheme is proposed in this paper for a DC microgrid system, which is enabled by Solid-State Transformer (SST). The proposed system includes distributed renewable energy resource (DRER) and distributed energy storage device (DESD). The proposed distributed control algorithm, which only relies on the local information and guarantees full utilization of each module in the system based on their characteristics, is applied to both SST and DC microgrid. To this end, a simulation platform is developed in MATLAB/Simulink, in which Photovoltaic (PV), fuel cell and battery are selected as the typical DRERs and DESD, respectively. Lastly, several typical case studies are carried out and the simulation results verify the proposed distributed power management.

  • Current sensorless power balance strategy for DC/DC converters in a cascaded multilevel converter based Solid State Transformer
    IEEE Transactions on Power Electronics, 2014
    Co-Authors: Xu She, Alex Q Huang, Xijun Ni
    Abstract:

    This letter proposes a current sensorless controller for balancing the power in the dc/dc stage of a cascaded multilevel converter based Solid State Transformer. It is revealed that the equalization of the active power component of duty cycles in the cascaded multilevel rectifier stage can be a good indicator of power balance in the dc/dc stage. Additionally, the power balance of the dc/dc stage can guarantee the voltage balance in the rectifier stage if the differences among the power devices are negligible. Based on this principle, a novel power balance controller without sensing any current in the dc/dc stage is proposed. In the end, experimental results in a seven-level three-stage Solid State Transformer are provided for verifying the proposed method.

  • review of Solid State Transformer technologies and their application in power distribution systems
    IEEE Journal of Emerging and Selected Topics in Power Electronics, 2013
    Co-Authors: Xu She, Alex Q Huang, Rolando Burgos
    Abstract:

    The Solid-State Transformer (SST), which has been regarded as one of the 10 most emerging technologies by Massachusetts Institute of Technology (MIT) Technology Review in 2010, has gained increasing importance in the future power distribution system. This paper presents a systematical technology review essential for the development and application of SST in the distribution system. The State-of-the-art technologies of four critical areas are reviewed, including high-voltage power devices, high-power and high-frequency Transformers, ac/ac converter topologies, and applications of SST in the distribution system. In addition, future research directions are presented. It is concluded that the SST is an emerging technology for the future distribution system.

  • Solid State Transformer in the future smart electrical system
    IEEE Power and Energy Society General Meeting, 2013
    Co-Authors: Xu She, Alex Huang
    Abstract:

    The concept of the Solid State Transformer has been investigated extensively in the past decade with the emphasis mainly focused on the circuit topology investigation. With the technology being more and more mature and acceptable, the application issue of Solid State Transformer in the future smart electrical system needs to be investigated. This paper characterizes and summarizes the main features of the Solid State Transformer, and correspondingly presents possible application areas of Solid State Transformer in the future smart electrical system. The future distribution system architecture is proposed and a new wind energy system is presented based on the multifunctional utilization of SST. Simulation results are given to demonstrate the proposal.

  • A cost effective power sharing strategy for a cascaded multilevel converter based Solid State Transformer
    2013 IEEE Energy Conversion Congress and Exposition, 2013
    Co-Authors: Xu She, Alex Q Huang
    Abstract:

    This paper proposes a power sharing strategy for DC/DC stage of a cascaded multilevel converter based Solid State Transformer. It is revealed that the equalization of the active power component of duty cycles in the cascaded multilevel rectifier stage can be a good indicator of power balance in the DC/DC stage. Additionally, the power balance of the DC/DC stage can guarantee the voltage balance in the rectifier stage if the differences among the power devices are negligible. Based on this principle, a novel power balance controller without sensing any current in the DC/DC stage is proposed. Both simulation and experimental results in a seven-level three-stage Solid State Transformer are provided for verifying the proposed method.