DC Solid State Transformer Based on Three-Level Power Module for Interconnecting MV and LV DC Distribution Systems

This article presents a dc solid state transformer based on three-level power module (PM) (TL-DCSST) for interconnection of medium-voltage dc (MVdc) and low-voltage dc distribution system. The proposed TL-DCSST adopts the low-voltage insulated-gate bipolar transistor (IGBTs) with excellent switching characteristics to build medium voltage PM and reduces the number of medium frequency transformer (MFT). This topology features inherent antibias mechanism for MFTs on the primary side, which saves the resonant capacitor at primary side. Meanwhile, the active front end is integrated to realize voltage and power regulation, low voltage ride-through and DC fault handling for MVdc side. In this article, the topology, operation principle, interleaving modulation, circuit parameter design, and control schemes are presented and analyzed comprehensively. At last, a prototype rated at 7 kW has been built and tested, and the experimental results verify effectiveness of the proposed TL-DCSST.

[1]  Fred Wang,et al.  Flux Balancing Control of Ungapped Nanocrystalline Core-Based Transformer in Dual Active Bridge Converters , 2020, IEEE Transactions on Power Electronics.

[2]  Guowei Liu,et al.  Modular Hybrid-Full-Bridge DC Transformer With Full-Process Matching Switching Strategy for MVdc Power Distribution Application , 2020, IEEE Transactions on Industrial Electronics.

[3]  Gabriel Ortiz.  High-Power DC-DC Converter Technologies for Smart Grid and Traction Applications , 2014 .

[4]  Majid Pahlevani,et al.  A Digital Active DC-Eliminating Method for DC/DC Converters , 2019, IEEE Transactions on Power Electronics.

[5]  Hamed Mohsenian Rad,et al.  Towards Building an Optimal Demand Response Framework for DC Distribution Networks , 2014, IEEE Transactions on Smart Grid.

[6]  A Q Huang,et al.  The Future Renewable Electric Energy Delivery and Management (FREEDM) System: The Energy Internet , 2011, Proceedings of the IEEE.

[7]  Xianggen Yin,et al.  A novel low voltage ride through strategy for cascaded power electronic transformer , 2019, Protection and Control of Modern Power Systems.

[8]  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).

[9]  Huai Wang,et al.  A Dual Active Bridge Converter With an Extended High-Efficiency Range by DC Blocking Capacitor Voltage Control , 2018, IEEE Transactions on Power Electronics.

[10]  Zhaohui Wang,et al.  A Three-Phase Modular Multilevel DC–DC Converter for Power Electronic Transformer Applications , 2017, IEEE Journal of Emerging and Selected Topics in Power Electronics.

[12]  Johann W. Kolar,et al.  Applicability of Solid-State Transformers in Today’s and Future Distribution Grids , 2019, IEEE Transactions on Smart Grid.

[13]  Hui Li,et al.  A Phase-Shifted Square Wave Modulation (PS-SWM) for Modular Multilevel Converter (MMC) and DC Transformer for Medium Voltage Applications , 2019, IEEE Transactions on Power Electronics.

[14]  J.W. Kolar,et al.  A compact, high voltage 25 kW, 50 kHz DC-DC converter based on SiC JFETs , 2008, 2008 Twenty-Third Annual IEEE Applied Power Electronics Conference and Exposition.

[15]  Sumit Dutta.  Controls and Applications of the Dual Active Bridge DC to DC Converter for Solid State Transformer Applications and Integration of Multiple Renewable Energy Sources , 2014 .

[16]  Wenhua Liu,et al.  A Modular Multilevel DC-Link Front-to-Front DC Solid-State Transformer Based on High-Frequency Dual Active Phase Shift for HVDC Grid Integration , 2017, IEEE Transactions on Industrial Electronics.

[17]  Johann W. Kolar,et al.  Generic Derivation of Dynamic Model for Half-Cycle DCM Series Resonant Converters , 2018, IEEE Transactions on Power Electronics.

[18]  P. K. Steimer,et al.  Conceptualization and Multiobjective Optimization of the Electric System of an Airborne Wind Turbine , 2013, IEEE Journal of Emerging and Selected Topics in Power Electronics.

[19]  Qing Xu,et al.  NPC based dual active bridge topology for integrating battery energy storage to utility gird , 2014, 2014 IEEE 27th Canadian Conference on Electrical and Computer Engineering (CCECE).

[20]  Zhengyu Lu,et al.  Three-level LLC series resonant DC/DC converter , 2005, IEEE Transactions on Power Electronics.

[21]  Marko Mogorovic,et al.  Sensitivity Analysis of Medium-Frequency Transformer Designs for Solid-State Transformers , 2019, IEEE Transactions on Power Electronics.

[22]  Yan Pan,et al.  A High Power Medium Voltage Resonant Dual Active Bridge for MVDC Ship Power Networks , 2017, IEEE Journal of Emerging and Selected Topics in Power Electronics.

[23]  Xudong Sun,et al.  Method to control flux balancing of high‐frequency transformers in dual active bridge dc–dc converters , 2018, The Journal of Engineering.

[24]  Kai Li,et al.  Analysis and Suppressing Method of Magnetizing Bias on High Frequency Transformer in Electric Energy Router , 2018, 2018 IEEE Energy Conversion Congress and Exposition (ECCE).

[25]  Guowei Liu,et al.  High-Frequency-Link DC Transformer Based on Switched Capacitor for Medium-Voltage DC Power Distribution Application , 2016, IEEE Transactions on Power Electronics.

[26]  Xu Yang,et al.  A Novel NPC Dual-Active-Bridge Converter With Blocking Capacitor for Energy Storage System , 2019, IEEE Transactions on Power Electronics.

[27]  Lu Qu,et al.  Input Voltage Sharing Control Scheme for Input Series and Output Parallel Connected DC–DC Converters Based on Peak Current Control , 2019, IEEE Transactions on Industrial Electronics.

[28]  Johann W. Kolar,et al.  Solid-State Transformers: On the Origins and Evolution of Key Concepts , 2016, IEEE Industrial Electronics Magazine.

[29]  Wenhua Liu,et al.  Overview of Dual-Active-Bridge Isolated Bidirectional DC–DC Converter for High-Frequency-Link Power-Conversion System , 2014, IEEE Transactions on Power Electronics.

[30]  Leila Parsa,et al.  Series-Input Parallel-Output Modular-Phase DC–DC Converter With Soft-Switching and High-Frequency Isolation , 2016, IEEE Transactions on Power Electronics.

[31]  Deepak Divan,et al.  Modular Universal Converter for MVDC Applications , 2018, 2018 IEEE Energy Conversion Congress and Exposition (ECCE).

[32]  Robert Whitehouse,et al.  Requirements of DC-DC Converters to facilitate large DC Grids , 2012 .

[33]  T. Friedli,et al.  Conceptualization and multi-objective optimization of the electric system of an Airborne Wind Turbine , 2011, 2011 IEEE International Symposium on Industrial Electronics.

[34]  Oscar Apeldoorn,et al.  Flux Balancing of Isolation Transformers and Application of “The Magnetic Ear” for Closed-Loop Volt–Second Compensation , 2014, IEEE Transactions on Power Electronics.

[35]  Mohammed Agamy,et al.  A Modular SiC High-Frequency Solid-State Transformer for Medium-Voltage Applications: Design, Implementation, and Testing , 2019, IEEE Journal of Emerging and Selected Topics in Power Electronics.

[36]  Hao Chen,et al.  Soft-switching solid state transformer (S4T) , 2016, 2016 IEEE Energy Conversion Congress and Exposition (ECCE).

[37]  Gabriel Ortiz,et al.  Design and Experimental Testing of a Resonant DC–DC Converter for Solid-State Transformers , 2017, IEEE Transactions on Power Electronics.

[38]  Kui Wang,et al.  System-Level Efficiency Evaluation of Isolated DC/DC Converters in Power Electronics Transformers for Medium-Voltage DC Systems , 2019, IEEE Access.

[39]  Jingjing Huang,et al.  Robust Circuit Parameters Design for the CLLC-Type DC Transformer in the Hybrid AC–DC Microgrid , 2019, IEEE Transactions on Industrial Electronics.