A Transformerless DC–DC Converter With Large Voltage Ratio for MV DC Grids

This paper proposes a transformerless dc-dc converter, which features a large voltage ratio, for medium-voltage dc (MVDC) applications. The proposed converter combines a boost converter with a series-parallel resonant converter which enables soft switching of the power switches and diodes. Further, the power switches and diodes of the proposed converter experience lower voltage stresses compared to the other topologies. The proposed converter is modular and, therefore, permits series and/or parallel connection of multiple units for the desired voltage and/or power ratings. This paper discusses the principles of operation, analysis, and design of the proposed converter. Simulation and experimental results are presented to demonstrate the effectiveness of the proposed converter.

[1]  Boon Teck Ooi,et al.  Developing DC Transmission Networks Using DC Transformers , 2010, IEEE Transactions on Power Delivery.

[2]  Wei Qian,et al.  A Switched-Capacitor DC–DC Converter With High Voltage Gain and Reduced Component Rating and Count , 2012, IEEE Transactions on Industry Applications.

[3]  R. Iravani,et al.  DC power systems: Challenges and opportunities , 2010, IEEE PES General Meeting.

[4]  Fernando Nuño García,et al.  Dynamic and Steady-State Models for the PRC-LCC Resonant Topology With a Capacitor as Output Filter , 2007, IEEE Transactions on Industrial Electronics.

[5]  Boon-Teck Ooi,et al.  Multiterminal LVDC system for optimal acquisition of power in wind-farm using induction generators , 2002 .

[6]  T. Mishima,et al.  Analysis, Design, and Performance Evaluations of an Edge-Resonant Switched Capacitor Cell-Assisted Soft-Switching PWM Boost DC–DC Converter and Its Interleaved Topology , 2013, IEEE Transactions on Power Electronics.

[7]  A.M. Pernia,et al.  Power Supply for a High-Voltage Application , 2008, IEEE Transactions on Power Electronics.

[8]  Seung-Ki Sul,et al.  A New Architecture for Offshore Wind Farms , 2008, IEEE Transactions on Power Electronics.

[9]  Liangzhong Yao,et al.  Large Offshore DFIG-Based Wind Farm With Line-Commutated HVDC Connection to the Main Grid: Engineering Studies , 2008, IEEE Transactions on Energy Conversion.

[10]  Friedrich Wilhelm Fuchs,et al.  Converter Systems for Fuel Cells in the Medium Power Range—A Comparative Study , 2010, IEEE Transactions on Industrial Electronics.

[11]  Prasad Enjeti,et al.  Analysis and design of electronic transformers for electric power distribution system , 1997, IAS '97. Conference Record of the 1997 IEEE Industry Applications Conference Thirty-Second IAS Annual Meeting.

[12]  W.L. Kling,et al.  HVDC Connection of Offshore Wind Farms to the Transmission System , 2007, IEEE Transactions on Energy Conversion.

[13]  D. Howe,et al.  Analysis of voltage output LCC resonant converters, including boost mode operation , 2003 .

[14]  Dragan Jovcic.  Step-up DC-DC converter for megawatt size applications , 2009 .

[15]  Xinbo Ruan,et al.  DC/DC Conversion Systems Consisting of Multiple Converter Modules: Stability, Control, and Experimental Verifications , 2009, IEEE Transactions on Power Electronics.

[16]  Il-Yop Chung,et al.  Integration of a bi-directional dc-dc converter model into a large-scale system simulation of a shipboard MVDC power system , 2009, 2009 IEEE Electric Ship Technologies Symposium.

[17]  Jonathan Robinson,et al.  Analysis and Design of an Offshore Wind Farm Using a MV DC Grid , 2010, IEEE Transactions on Power Delivery.

[18]  R. Gules,et al.  Voltage Multiplier Cells Applied to Non-Isolated DC–DC Converters , 2008, IEEE Transactions on Power Electronics.

[19]  Ahmed M. Massoud,et al.  Multiple-Module High-Gain High-Voltage DC–DC Transformers for Offshore Wind Energy Systems , 2011, IEEE Transactions on Industrial Electronics.

[20]  J. W. Kolar,et al.  1 Megawatt, 20 kHz, isolated, bidirectional 12kV to 1.2kV DC-DC converter for renewable energy applications , 2010, The 2010 International Power Electronics Conference - ECCE ASIA -.

[21]  Alex Q. Huang,et al.  Analysis and Comparison of Medium Voltage High Power DC/DC Converters for Offshore Wind Energy Systems , 2013, IEEE Transactions on Power Electronics.

[22]  Abdelrahman Hagar.  A New Family of Transformerless Modular DC-DC Converters for High Power Applications , 2011 .