A unidirectional DC-DC autotransformer for DC grid application

Conventional unidirectional DC-DC converters for DC grid application employ DC-AC-DC two-stage conversion technology and suffer from high converter cost and power loss. To solve these issues, a unidirectional step-up DC-DC autotransformer (UUDAT) and a unidirectional step-down DC-DC autotransformer (DUDAT) are studied. The UUDAT and DUDAT are composed of a series connection of diode bridges and voltage source converters. Topologies of UUDAT and DUDAT are detailed. The harmonic and un-controllability issues are discussed. Control and possible application scenarios for UUDAT and DUDAT are depicted. DC fault isolation mechanism and the methods of dimensioning the voltage and power ratings of the components in UUDAT and DUDAT are studied. Extensive simulations on power system level and experiments on a UUDAT and DUDAT prototype verified their technical feasibility.

[1]  Weixing Lin,et al.  DC–DC Autotransformer With Bidirectional DC Fault Isolating Capability , 2016, IEEE Transactions on Power Electronics.

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

[3]  Stephen J. Finney,et al.  Review of dc-dc converters for multi-terminal HVDC transmission networks , 2016 .

[4]  Dragan Jovcic,et al.  DC fault performance and cost analysis of DC grids for connecting multiple offshore wind farms , 2013, 2013 IEEE Grenoble Conference.

[5]  Rik W. De Doncker,et al.  Development and demonstration of a medium-voltage high-power DC-DC converter for DC distribution systems , 2014, 2014 IEEE 5th International Symposium on Power Electronics for Distributed Generation Systems (PEDG).

[6]  Lie Xu,et al.  Reduced switching-frequency modulation and circulating current suppression for modular multilevel converters , 2012, PES T&D 2012.

[7]  Shijie Cheng,et al.  Multiport DC–DC Autotransformer for Interconnecting Multiple High-Voltage DC Systems at Low Cost , 2015, IEEE Transactions on Power Electronics.

[8]  Andre Schon,et al.  A new HVDC-DC converter with inherent fault clearing capability , 2013, 2013 15th European Conference on Power Electronics and Applications (EPE).

[9]  Zhe Chen,et al.  Design of Protective Inductors for HVDC Transmission Line Within DC Grid Offshore Wind Farms , 2013, IEEE Transactions on Power Delivery.

[10]  Mark M. Bakran,et al.  Average loss calculation and efficiency of the new HVDC auto transformer , 2014, 2014 16th European Conference on Power Electronics and Applications.

[11]  Lu Zhang,et al.  LCL DC/DC Converter for DC Grids , 2013, IEEE Transactions on Power Delivery.

[12]  Timothy C. Green,et al.  A Compact Modular Multilevel DC–DC Converter for High Step-Ratio MV and HV Use , 2018, IEEE Transactions on Industrial Electronics.

[13]  Nageswar Rao,et al.  HIGH-FREQUENCY OPERATION OF A DC/AC/DC SYSTEM FOR HVDC APPLICATIONS , 2016 .

[14]  Andre Schon,et al.  High power HVDC-DC converters for the interconnection of HVDC lines with different line topologies , 2014, 2014 International Power Electronics Conference (IPEC-Hiroshima 2014 - ECCE ASIA).

[15]  Liangzhong Yao,et al.  Step-up unidirectional DC-DC autotransformer for HVDC applications , 2016, 2016 IEEE 8th International Power Electronics and Motion Control Conference (IPEMC-ECCE Asia).

[16]  Claus Leth Bak,et al.  Selection of DC/DC converter for offshore wind farms with MVDC power collection , 2017, 2017 19th European Conference on Power Electronics and Applications (EPE'17 ECCE Europe).

[17]  Carlo Cecati,et al.  DC nanogrid for renewable sources with modular DC/DC LLC converter building block , 2017 .

[18]  Mark-M. Bakran,et al.  A new HVDC-DC converter for the efficient connection of HVDC networks , 2013 .

[19]  Guangfu Tang,et al.  The Hybrid-Cascaded DC–DC Converters Suitable for HVdc Applications , 2015, IEEE Transactions on Power Electronics.

[20]  Javier Sebastian,et al.  Different purpose design strategies and techniques to improve the performance of a Dual Active Bridge with phase-shift control , 2014, COMPEL 2014.

[21]  Jürgen Häfner,et al.  Proactive Hybrid HVDC Breakers - A key Innovation for Reliable HVDC Grids , 2011 .

[22]  Jinyu Wen,et al.  Wide-Area Damping Controller for Power System Interarea Oscillations: A Networked Predictive Control Approach , 2015, IEEE Transactions on Control Systems Technology.

[23]  Rik W. De Doncker,et al.  Comparison of the Modular Multilevel DC Converter and the Dual-Active Bridge Converter for Power Conversion in HVDC and MVDC Grids , 2015, IEEE Transactions on Power Electronics.

[24]  Jinyu Wen,et al.  Enhanced Independent Pole Control of Hybrid MMC-HVdc System , 2018, IEEE Transactions on Power Delivery.

[25]  J. A. Ferreira,et al.  The Multilevel Modular DC Converter , 2013, IEEE Transactions on Power Electronics.

[26]  Dragan Jovcic,et al.  Dual Channel Control With DC Fault Ride Through for MMC-Based, Isolated DC/DC Converter , 2017, IEEE Transactions on Power Delivery.

[27]  Peter W. Lehn,et al.  A Bidirectional Modular Multilevel DC–DC Converter of Triangular Structure , 2015, IEEE Transactions on Power Electronics.

[28]  Zhe Chen,et al.  Operation and Control of a DC-Grid Offshore Wind Farm Under DC Transmission System Faults , 2013, IEEE Transactions on Power Delivery.

[29]  Da Xie,et al.  Fast Voltage-Balancing Control and Fast Numerical Simulation Model for the Modular Multilevel Converter , 2015, IEEE Transactions on Power Delivery.

[30]  Fei Xiao,et al.  A Modular Multilevel DC–DC Converter Topology With a Wide Range of Output Voltage , 2017, IEEE Transactions on Power Electronics.

[31]  Qingru Qi,et al.  Study of Some Key Issues Related to Large-Scale Wind Power Grid Integration in China , 2012 .