Research on DC Voltage Balancing Strategy of Single-Phase Cascaded Solid State Transformer

doi:10.11985/2017.05.003

Abstract

Abstract:

The disadvantages in power system with traditional industrial frequency transformer can be resolved by SST (solid state transformer). Cascaded SST can be transformerless connected to the high voltage grid. However, the output performance and reliability of cascaded grid-connected inverter are seriously influenced by DC voltage balancing problem which exists in cascaded configuration. Firstly, circuit topology, operating principle and mathematical model of single-phase cascaded SST are analyzed. Then, active power adjusting ability of DC voltage balancing methods are compared. Finally, suitable DC voltage balancing method is confirmed. This method can balance the DC voltages even under complex condition. Experimental results verify the feasibility and validity of this method.

Key words: Solid state transformer, DC voltage balancing control, active vector correction method, cascaded H-bridge

CLC Number:

TM41

Zhendong Ji,Dongye Li,Yichao Sun,Jianfeng Zhao,Yunkai Huang. Research on DC Voltage Balancing Strategy of Single-Phase Cascaded Solid State Transformer[J]. Journal of Electrical Engineering, 2017, 12(5): 15-21.

Figures/Tables 11

Fig.1

Fig.2

Fig.3

Fig.4

Fig.5

Fig.6

Fig.7

Fig.8

Fig.9

Fig.10

Fig.11

References 16

[1]	王丹. 配电系统电子电力变压器[D]. 华中科技大学, 2006.
[2]	Xu S. Control and design of a high voltage solid state transformer and its integration with renewable energy resources and microgrid system[D]. North Carolina State University, 2013.
[3]	Iov F, Blaabjerg F, Clare J, et al. UNIFLEX-PM-A key-enabling technology for future european electricity networks[J]. Epe Journal: European Power Electronics and Drives Association Journal, 2015,19(4):6-16.
[4]	Besselmann T, Mester A, Dujic D. Power electronic traction transformer: efficiency improvements under light-load conditions[J]. IEEE Transaction on Power Electronics, 2013,29(8):3971-3981.
[5]	Lai J S, Maitra A, Mansoor A, et al. Multilevel intelligent universal transformer for medium voltage applications[C]. IEEE Industry Applications Conference, HongKong, 2005: 1893-1899.
[6]	耿俊成, 刘文华, 袁志昌 .链式 STATCOM 电容电压不平衡现象研究(一)仿真和试验[J]. 电力系统自动化, 2003,27(16):53-57.
	Geng Juncheng, Liu Wenhua, Yuan Zhichang. Research on the voltage unbalance of DC capacitors of cascade statcomPart one simulations and experiments[J]. Automation of Electric Power Systems, 2003,27(16):53-57.
[7]	胡应宏, 任佳佳, 王建赜. 级联STATCOM阀组直流侧电压不平衡现象及原因分析[J]. 电力系统自动化, 2011,35(21):96-100.
	Hu Yinghong, Ren Jiajia, Wang Jianze. Analysis of voltage unbalance phenomenon and causes in cluster DC-link of cascade H-bridge STATCOM[J]. Automation of Electric Power Systems, 2011,35(21):96-100.
[8]	李祎春, 刘文里, 霍霖, 等. 基于ANSYS的大型电力变压器外绕组辐向稳定[J]. 电气应用, 2016,35(3):40-44.
[9]	刘文华, 宋强, 滕乐天. 基于链式逆变器的50MV·A 静止同步补偿器的直流电压平衡控制[J]. 中国电机工程学报, 2004,24(4):145-150.
	Liu Wenhua, Song Qiang, Teng Letian. Balancing control of DC voltages of 50MV·A STATCOM based on cascade multilevel inverters[J]. Proceedings of the CSEE, 2004,24(4):145-150.
[10]	Rivera S, Wu B, Kouro S, et al. Cascaded H-bridge multilevel converter topology and three-phase balance control for large scale photovoltaic systems[C]. IEEE International Symposium on Power Electronics for Distributed Generation Systems, Aalborg, Danmark, 2012: 690-697.
[11]	Kouro S, Wu B, Moya A, et al. Control of a cascaded H-bridge multilevel converter for grid connection of photovoltaic systems[C]. Annual Conference of IEEE Industrial Electronics, Porto, Portuguesa, 2009: 3976-3982.
[12]	Peng F, Lai J. A multilevel voltage-source inverter with separates dc sources for static var generation[J]. IEEE Transaction on Industry Applications, 1996,32(5):1130-1138.
[13]	Aquila A D, Liserre M, Monopoli V G, et al. Overview of PI-based solutions for the control of DC buses of a single-phase H-bridge multilevel active rectifier[J]. IEEE Transactions on Industry Applications, 2008,44(3):857-866.
[14]	陶兴华, 李永东, 孙敏. 一种H桥级联型PWM整流器的直流母线电压平衡控制新方法[J]. 电工技术学报, 2011,26(8):85-90.
	Tao Xinghua, Li Yongdong, Sun Min. A novel DC-link voltages balancing control method for cascaded H-bridge rectifier[J]. Transactions of China Electrotechnical Society, 2011,26(8):85-90.
[15]	Zhao T, Wang G, Bhattacharya S. Voltage and power balance control for a cascaded H-bridge converter-based solid-state transformer[J]. IEEE Transaction on Power Electronics, 2013,28(4):1523-1532.
[16]	宫力, 康勇, 陈晶晶. 链式STATCOM直流电容电压分布式控制[J]. 电工技术学报, 2011,26(10):217-223.
	Gong Li, Kang Yong, Chen Jingjing. DC capacitor voltage distributed control system for cascaded multilevel STATCOM[J]. Transactions of China Electrotechnical Society, 2011,26(10):217-223.