Abstract Solid state transformer (SST), as one of the most important equipment for smart grid application, will play a more important role in the future power system. In order to solve some issues existed in the three-phase cascaded modular SST, such as the complexity of the topology, difficulty in controlling, voltage and power unbalance of each H-bridge module,a simple three-phase SST topology based on high-voltage silicon carbide (SiC) power semiconductor device is adopted in this paper. The simple topology revitalizes the traditional topology and has a great practical prospect. Its mathematical model and normal control strategy are established and analyzed in this paper, and then a control strategy under unbalanced grid voltages by suppressing the negative-sequence currents at the grid side of SST is presented. Simulation results in PSIM software have verified the effectiveness of the two control strategies. Finally the experiment platform based on SiC devices was built, and the front-end rectifier was verified by experiment results.
Yu Chenghao,Wang Yubin,Li Houzhi. The Three-Phase Solid State Transformer Topology Based on High-Voltage SiC Device and Control Strategy Under Unbalanced Grid Voltages[J]. Transactions of China Electrotechnical Society, 2017, 32(增刊2): 111-118.
[1] 余晓丹, 徐宪东, 陈硕翼, 等. 综合能源系统与能源互联网简述[J]. 电工技术学报, 2016, 31(1): 1-13. Yu Xiaodan, Xu Xiandong, Chen Shuoyi, et al. A brief review to integrated energy system and energy internet[J]. Transactions of China Electrotechnical Society, 2016, 31(1): 1-13. [2] Huang A Q, Crow M L, Heydt G T, et al. The future renewable electric energy delivery and management (FREEDM) system: the energy internet[J]. Procee- dings of the IEEE, 2011, 99(1): 133-148. [3] Huang A Q. FREEDM system-a vision for the future grid[C]//IEEE Power & Energy Society General Meeting, Providence, RI, 2010: 1-4. [4] 张明锐, 刘金辉, 金鑫. 应用于智能微网的SVPWM固态变压器研究[J]. 电工技术学报, 2012, 27(1): 90-97. Zhang Mingrui, Liu Jinhui, Jin Xin. Research on the SVPWM solid state transformer applied in smart micro-grid[J]. Transactions of China Electrotechnical Society, 2012, 27(1): 90-97. [5] 兰征, 涂春鸣, 肖凡, 等. 电力电子变压器对交直流混合微网功率控制的研究[J]. 电工技术学报, 2015, 30(23): 50-57. Lan Zheng, Tu Chunming, Xiao Fan, et al. The power control of power electronic transformer in hybrid AC-DC microgrid[J]. Transactions of China Electro- technical Society, 2015, 30(23): 50-57. [6] Kang M, Enjeti P N, Pitel I J. Analysis and design of electronic transformers for electric power distribution system[J]. IEEE Transactions on Power Electronics, 1999, 14(6): 1133-1141. [7] She X, Huang A Q, Ni X. Current sensorless power balance strategy for DC/DC converters in a cascaded multilevel converter based solid state transformer[J]. IEEE Transactions on Power Electronics, 2014, 29(1): 17-22. [8] 王杉杉, 王玉斌, 林意斐, 等. 级联型电力电子变压器电压与功率均衡控制方法[J]. 电工技术学报, 2016, 31(22): 92-99. Wang Shanshan, Wang Yubin, Lin Yifei, et al. Vol- tage and power balance control for cascaded mul- tilevel converter based power electronic transformer [J]. Transactions of China Electrotechnical Society, 2016, 31(22): 92-99. [9] 吴剑, 石健将, 张至愚. 三相模块级联型固态变压器均压/均功率控制策略研究[J]. 电源学报, 2015, 13(2): 17-26. Wu Jian, Shi Jianjiang, Zhang Zhiyu. Research on voltage and power balance control for three-phase cascaded modular soild-state transformer[J]. Journal of Power Supply, 2015, 13(2): 17-26. [10] 盛况, 郭清, 张军明, 等. 碳化硅电力电子器件在电力系统的应用展望[J]. 中国电机工程学报, 2012, 32(30): 1-7. Sheng Kuang, Guo Qing, Zhang Junming, et al. Development and prospect of SiC power devices in power grid[J]. Proceedings of the CSEE, 2012, 32(30): 1-7. [11] Palmour J W, Cheng L, Pala V, et al. Silicon carbide power MOSFETs: breakthrough performance from 900V up to 15kV[C]//IEEE 26th International Symposium on Power Semiconductor Devices & IC’s, Waikoloa, HI, 2014: 79-82. [12] Sung W, Wang J, Huang A Q, et al. Design and investigation of frequency capability of 15kV 4H-SiC IGBT[C]//IEEE 21st International Symposium on Power Semiconductor Devices & IC’s, Barcelona, Spain, 2009: 271-274. [13] Mainali K, Tripathi A, Madhusoodhanan S, et al. A transformerless intelligent power substation: a three- phase sst enabled by a 15kV SiC IGBT[J]. IEEE Power Electronics Magazine, 2015, 2(3): 31-43. [14] 张崇巍, 张兴. PWM 整流器及其控制[M]. 北京: 机械工业出版社, 2002. [15] Kheraluwala M H, Gasgoigne R W, Divan D M, et al. Performance characterization of a high power dual active bridge DC/DC converter[C]//IEEE Industry Applications Society Annual Meeting, Seattle, WA, 1990: 1267-1273. [16] Alonso A R, Sebastian J, Lamar D G, et al. An overall study of a dual active bridge for bidirectional DC/DC conversion[C]//IEEE Energy Conversion Con- gress & Exposition, Atlanta, GA, 2010: 1129-1135. [17] Morán L, Ziogas P D, Joos G. Design aspects of synchronous PWM rectifier-inverter systems under unbalanced input voltage conditions[J]. IEEE Transactions on Industry Applications, 1992, 28(6): 1286-1293.
2017, Vol. 32 
