Modularized Three-Phase Semiconductor Transformer with Bidirectional Power Flow for Medium Voltage Application

This paper describes a prototype of modularized three-phase semiconductor transformer that was developed in the lab for feasibility study. The developed prototype is composed of three units of single-phase semiconductor transformer coupled in Y-connection. Each single-phase unit has multiple units of high-voltage high-frequency resonant AC–DC converter, a low-voltage hybrid-switching DC–DC converter, and a low-voltage hybrid-switching DC–AC inverter. Also, each single-phase unit has two digital signal processor (DSP) boards to control converter operation and to acquire monitoring data. The monitoring system was developed based on LabView by using controller area network (CAN) communication between the DSP board and the personal computer (PC). Through diverse experimental analyses it was verified that the prototype operates with proper performance under normal and sag conditions. The developed prototype confirms the possibility of fabricating a commercial high-voltage high-power semiconductor transformer by increasing the number of series-connected converter modules in high-voltage side and improving the system efficiency with a new switching device such as an SiC device.

[1]  J. W. Kolar,et al.  Soft-switching techniques for medium-voltage isolated bidirectional DC/DC converters in solid state transformers , 2012, IECON 2012 - 38th Annual Conference on IEEE Industrial Electronics Society.

[2]  Hui Li,et al.  High-Frequency Transformer Isolated Bidirectional DC–DC Converter Modules With High Efficiency Over Wide Load Range for 20 kVA Solid-State Transformer , 2011, IEEE Transactions on Power Electronics.

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

[4]  Bin Wu,et al.  Power and Voltage Balance Control of a Novel Three-Phase Solid-State Transformer Using Multilevel Cascaded H-Bridge Inverters for Microgrid Applications , 2016, IEEE Transactions on Power Electronics.

[5]  R. Ayyanar,et al.  A DC–DC Multiport-Converter-Based Solid-State Transformer Integrating Distributed Generation and Storage , 2013, IEEE Transactions on Power Electronics.

[6]  Hao Yuan,et al.  Research on voltage and power balance control for cascaded modular solid-state transformer , 2011, IEEE Transactions on Power Electronics.

[7]  Jun Wang,et al.  270 kVA Solid State Transformer Based on 10 kV SiC Power Devices , 2007, 2007 IEEE Electric Ship Technologies Symposium.

[8]  Jih-Sheng Lai,et al.  Multilevel intelligent universal transformer for medium voltage applications , 2005, Fourtieth IAS Annual Meeting. Conference Record of the 2005 Industry Applications Conference, 2005..

[9]  Alex Q. Huang,et al.  On Integration of Solid-State Transformer With Zonal DC Microgrid , 2012, IEEE Transactions on Smart Grid.

[10]  Jinjun Liu,et al.  Control and Experiment of an H-Bridge-Based Three-Phase Three-Stage Modular Power Electronic Transformer , 2016, IEEE Transactions on Power Electronics.

[11]  Jun-Young Lee,et al.  An Isolated DC/DC Converter Using High-Frequency Unregulated $LLC$ Resonant Converter for Fuel Cell Applications , 2011, IEEE Transactions on Industrial Electronics.

[12]  B. M. Han,et al.  New Intelligent Semiconductor Transformer With Bidirectional Power-Flow Capability , 2014, IEEE Transactions on Power Delivery.

[13]  Hui Li,et al.  Distributed Digital Control of Modular-Based Solid-State Transformer Using DSP+FPGA , 2013, IEEE Transactions on Industrial Electronics.

[14]  K.F. Hoffmann,et al.  High frequency power switch - improved performance by MOSFETs and IGBTs connected in parallel , 2005, 2005 European Conference on Power Electronics and Applications.

[15]  Jun-Young Lee,et al.  A 10-kW Two-Stage Isolated/Bidirectional DC/DC Converter With Hybrid-Switching Technique , 2013, IEEE Transactions on Industrial Electronics.

[16]  Gangyao Wang,et al.  3-D Space Modulation With Voltage Balancing Capability for a Cascaded Seven-Level Converter in a Solid-State Transformer , 2011, IEEE Transactions on Power Electronics.

[17]  Alex Q. Huang,et al.  Voltage and Power Balance Control for a Cascaded H-Bridge Converter-Based Solid-State Transformer , 2013, IEEE Transactions on Power Electronics.

[18]  Arindam Maitra,et al.  Intelligent Universal Transformer design and applications , 2009 .

[19]  Alex Q. Huang,et al.  High voltage Si/SiC hybrid switch: An ideal next step for SiC , 2015, 2015 IEEE 27th International Symposium on Power Semiconductor Devices & IC's (ISPSD).