Abstract:Compared with the quarter-symmetry SHEPWM method of multilevel inverters, half-cycle symmetry SHEPWM method has infinite solutions. Compared with asymmetry SHEPWM method, half-cycle symmetry SHEPWM equations need less computations and data storage space. Therefore the half-cycle symmetry SHEPWM method is more attractive. Take a five-level inverter as an example, with a case of 20 switching points in half-cycle and M=0.75, this paper studies in detail the formulation and solutions of half-cycle symmetry multilevel SHEPWM problems. Simulations based on PSIM 6 package are carried out. A five-level cascade inverter prototype is constructed and experimentally investigated based on the same solutions used in the simulations. Experimental results agree well with the simulations, and prove the validity and practicability of the proposed method.
[1] 李永东, 肖曦, 高跃. 大容量多电平变换器: 原理·控制·应用[M]. 北京: 科学出版社, 2005. [2] 王琛琛, 李永东, 高跃. 基于通用多电平SVPWM算法的三电平无速度传感器矢量控制系统[J]. 电工技术学报, 2007, 22(9): 107-111. [3] Li Li, Dariusz Czarkowski, Liu Yaguang, et al. Multilevel selective harmonic elimination PWM technique in series-connected voltage inverters[J]. Transactions on Industry Applications, 2000, 36(1): 160-170. [4] Tolbert L M, Chiasson J, Kenzie Mc K, et al. Elimination of harmonics in a multilevel converter with nonequal DC sources[J]. IEEE Transactions on Industrial Applications, 2005, 41(1): 75-82. [5] Chiasson J N, Tolbert L M, Kenzie Mc K, et al. Elimination of harmonics in a multilevel converter using the theory of symmetric polynomials and resultants[J]. IEEE Transactions on Control Systems Technology, 2005, 13(2): 216-223. [6] Liang T J, O’Connell R M, Hoft R G. Inverter harmonic reduction using Walsh function harmonic elimination method[J]. IEEE Transactions on Power Electronics, 1997, 12(6): 971-982. [7] 郑春芳, 张波, 丘东元. 基于Walsh变换的多电平逆变器谐波消除技术(English) [J]. 电工技术学报, 2006, 21(7): 121-126. [8] Toshiji Kato. Sequential homotopy-based computation of multiple solutions for selected harmonic elimination in PWM inverters[J]. IEEE Transactions on Circuit and Systems-I: Fundamental Theory and Applications, 1999, 46(5): 586-593. [9] Kinattingal Sundareswaran, Krishna Jayant, Shanavas T N. Inverter harmonic elimination through a colony of continuously exploring ants[J]. IEEE Transactions on Industrial Electronics, 2007, 54(5): 2558-2565. [10] 张艳莉, 费万民, 吕征宇, 等. 三电平逆变器SHEPWM方法及其应用研究[J]. 电工技术学报, 2004, 19 (1): 16-17. [11] 费万民, 张艳莉, 阮新波, 等.三电平逆变器SHEPWM非线性方程组的求解[J]. 中国电机工程学报, 2008, 28(6): 62-68. [12] 费万民, 吕征宇, 姚文熙. 多电平逆变器特定谐波消除脉宽调制方法的仿真研究[J]. 中国电机工程学报, 2004, 24(1): 102-106. [13] 费万民, 阮新波, 张艳莉, 等. 多电平逆变器特定谐波消除脉宽调制方法的初值问题研究[J]. 中国电机工程学报, 2007, 27(13): 87-92. [14] 费万民, 张艳莉, 都小利. 五电平逆变器特定谐波消除脉宽调制方法研究[J]. 电工技术学报, 2009, 24(2): 85-93. [15] Jason R Wells, Brett M Nee, Patrick L Chapman, et al. Selective harmonic control: a general problem formation and selected solutions[J]. IEEE Transactions on Power Electronics, 2005, 20(6): 1337-1345. [16] 张永昌, 赵争鸣, 张颖超. 三电平逆变器SHEPWM多组解特性比较及实验[J]. 电工技术学报, 2007, 22 (3):60-65. [17] 张永昌, 赵争鸣. 三电平逆变器SHEPWM多组解计算方法[J]. 电工技术学报, 2007, 22(1): 74-78. [18] Mohamed S A Dahidah, Vassilios G Agelidis, Machavaram V Rao. On abolishing symmetry require- ments in the formulation of a five-level selective harmonic elimination pulse-width modulation technique[J]. IEEE Transactions on Power Electronics, 2006, 21(6): 1833-1837. [19] 邓建中, 葛人杰, 程正兴. 计算方法[M]. 西安: 西安交通大学出版社, 1985.