Energization and Start-up of Modular Three-stage Solid State Transformers

Grid-connection and startup of solid state transformers (SST) based on modular topologies are studied in this work. A simple solution is implemented to feed the auxiliary electronics (i.e. sensors, control boards, drivers, etc.) of each SST module. It is based on feeding this circuitry from the DC links of the module using Auxiliary Power Supplies (APS). However, this structure leads to a problematic energization of the SST due to the threshold input voltage of the APS. Before the DC link capacitors are charged to this voltage threshold, the APSs are not functional and consequently SST energization and connection to the grid are performed without monitoring. Although startup in this situation is problematic, adequate procedure can prevent unwanted transients. In this paper, a step-by-step simple procedure is proposed for energizing a three-stage SST based on a Cascaded H-Bridge (CHB) modular topology. Simulation results as well as experimental tests are presented.

[1]  Alberto Rodriguez,et al.  Design and implementation of the control of an MMC-based solid state transformer , 2015, 2015 IEEE 13th International Conference on Industrial Informatics (INDIN).

[2]  Z. Q. Zhu,et al.  Power Electronic Transformer-Based Railway Traction Systems: Challenges and Opportunities , 2017, IEEE Journal of Emerging and Selected Topics in Power Electronics.

[3]  William McMurray,et al.  The Thyristor Electronic Transformer: a Power Converter Using a High-Frequency Link , 1971 .

[4]  Alex Q. Huang,et al.  7.2-kV Single-Stage Solid-State Transformer Based on the Current-Fed Series Resonant Converter and 15-kV SiC mosfets , 2019, IEEE Transactions on Power Electronics.

[5]  Francesco Agostini,et al.  Integration technologies for a medium voltage modular multi-level converter with hot swap capability , 2015, 2015 IEEE Energy Conversion Congress and Exposition (ECCE).

[6]  Hao Chen,et al.  Dyna-C: A Minimal Topology for Bidirectional Solid-State Transformers , 2017, IEEE Transactions on Power Electronics.

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

[8]  Hui Li,et al.  Study on the start-up schemes for the three-stage solid state transformer applications , 2012, 2012 IEEE Energy Conversion Congress and Exposition (ECCE).

[9]  H. du T. Mouton,et al.  The solid-state transformer concept: A new era in power distribution , 2009, AFRICON 2009.

[10]  Alberto Rodriguez,et al.  Auxiliary power supply based on a modular ISOP flyback configuration with very high input voltage , 2016, 2016 IEEE Energy Conversion Congress and Exposition (ECCE).

[11]  Cassiano Rech,et al.  Auxiliary power supply for solid state transformers , 2016, 2016 IEEE International Conference on Electronics, Circuits and Systems (ICECS).

[12]  Subhashish Bhattacharya,et al.  Start-up scheme for solid state transformers connected to medium voltage grids , 2015, 2015 IEEE Applied Power Electronics Conference and Exposition (APEC).

[13]  H. Akagi,et al.  A Bidirectional DC–DC Converter for an Energy Storage System With Galvanic Isolation , 2007, IEEE Transactions on Power Electronics.

[14]  Zhan Wang,et al.  A Start-Up Scheme for a Three-Stage Solid-State Transformer With Minimized Transformer Current Response , 2012, IEEE Transactions on Power Electronics.

[15]  Alex Q. Huang,et al.  15 kV SiC MOSFET: An enabling technology for medium voltage solid state transformers , 2017 .

[16]  J. Taufiq,et al.  Power Electronics Technologies for Railway Vehicles , 2007, 2007 Power Conversion Conference - Nagoya.

[17]  Frede Blaabjerg,et al.  Overview of Control and Grid Synchronization for Distributed Power Generation Systems , 2006, IEEE Transactions on Industrial Electronics.

[18]  Fernando Briz,et al.  Energization and Start-Up of CHB-Based Modular Three-Stage Solid-State Transformers , 2018, IEEE Transactions on Industry Applications.

[19]  Roderick J. Garcia Montoya,et al.  An evaluation of selected solid-state transformer topologies for electric distribution systems , 2015, 2015 IEEE Applied Power Electronics Conference and Exposition (APEC).

[20]  Raja Ayyanar,et al.  Topology comparison for Solid State Transformer implementation , 2010, IEEE PES General Meeting.

[21]  Fernando Briz,et al.  Design and construction of a DAB using SiC MOSFETs with an isolation of 24 kV for PET applications , 2017, 2017 19th European Conference on Power Electronics and Applications (EPE'17 ECCE Europe).

[22]  Alberto Rodriguez,et al.  Modular Power Electronic Transformers: Modular Multilevel Converter Versus Cascaded H-Bridge Solutions , 2016, IEEE Industrial Electronics Magazine.

[23]  Sukumar Mishra,et al.  Modeling and design of solid state smart transformer for microgrid , 2018, 2018 IEEMA Engineer Infinite Conference (eTechNxT).

[24]  Marco Liserre,et al.  Smart Transformer reliability and efficiency through modularity , 2016, 2016 IEEE 8th International Power Electronics and Motion Control Conference (IPEMC-ECCE Asia).

[25]  Rolando Burgos,et al.  Review of Solid-State Transformer Technologies and Their Application in Power Distribution Systems , 2013, IEEE Journal of Emerging and Selected Topics in Power Electronics.