Abstract：A space vector PWM (SVPWM) algorithm based on virtual vectors of gh coordinate system is proposed for the three-level neutral-point-clamped (NPC) inverter. This strategy can remove the low-frequency oscillations that appear on the neutral-point voltage of the NPC inverter and it can be used for any nonlinear load conditions. In order to lower the switch frequency and avoid the abrupt change of output voltage vectors, an optimal sequences of the output voltage vecotrs based on the algorithm is proposed. It requires only a simple coordinate transformation and arithmetic to determine the sector in which the reference voltage vector is and the effective time calculation of the output voltage vectors. The disadvantages of a lot of calculation of the trigonometric functions and the estimation of the sectors for the traditional SVPWM algorithm are avoided after transforming the whole space vector diagram into the first sextant. And in order to eliminate any possible imbalance of the capacitors voltage , a close loop for achieving volatge balance based on changing the effective time of the positive and the negative small vectors is proposed. The proposed method is verified by simulation and experimental results.
张志, 谢运祥, 乐江源, 陈林. 消除中点电位低频振荡的三电平逆变器空间矢量脉宽调制方法[J]. 电工技术学报, 2011, 26(3): 103-109.
Zhang Zhi, Xie Yunxiang, Le Jiangyuan, Chen Lin. SVPWM Method of Removing the Low-Frequency Oscillations of Neutral Point Voltage for Three-Level NPC Inverter. Transactions of China Electrotechnical Society, 2011, 26(3): 103-109.
[1] Lai J S, Peng F Z. Multilevel converters-a new breed of power converters[J]. IEEE Transactions on Industry Applications, 1996, 32(3): 509-517. [2] 李永东. 大容量多电平变换器& #x02014; 原理. 控制. 应用[M]. 北京: 科学出版社, 2005. [3] 詹长江, 秦荃华, 韩英铎, 等. 三电平脉宽调制高频整流器系统数学模型及仿真分析[J]. 中国电机工程学报, 1999, 19(7): 45-48. [4] 金红元, 邹云屏, 林磊, 等. 三电平PWM整流器双环控制技术及中点电压平衡控制技术的研究[J]. 中国电机工程学报, 2006, 26 (20): 64-68. [5] Suh J H, Choi H C, Hyun D S. A new simplified space-vector PWM method for three-level inverters[J]. IEEE Transactions on Power Electronics, 2001, 16(4): 545-550. [6] 赵辉, 李瑞, 王红君, 等. 60& #x000b0; 坐标系下三电平逆变器SVPWM方法的研究[J]. 中国电机工程学报, 2008, 28 (24): 39-45. [7] 姜卫东, 王群京, 史晓锋, 等. 中点钳位型三电平逆变器在空间矢量调制时中点电位的低频振荡[J]. 中国电机工程学报, 2009, 29 (3): 49-55. [8] 宋文祥, 陈国呈, 束满堂, 等. 中点钳位式三电平逆变器空间矢量调制及其中点控制研究[J]. 中国电机工程学报, 2006, 26 ( 5): 105-109. [9] Celanovic N, Boroyevich D. A fast space-vector modulation algorithm for multilevel three-phase converters[J]. IEEE Transactions on Industry Applications, 2001, 37(2): 637-641. [10] Steinke J K. Switching frequency optimal PWM control of a three-level inverter[J]. IEEE Transactions on Power Electronics, 1992, 7(3): 487-496. [11] 宋文祥, 陈国呈, 武慧, 等. 一种具有中点电位平衡功能的三电平空间矢量调制方法及其实现[J]. 中国电机工程学报, 2006, 26(12): 95-100. [12] Celanovic N. A comprehensive study of neutral-point voltage balancing problem in three-level neutral- point-clamped voltage source PWM inverters[J]. IEEE Transactions on Power Electronics, 2000, 15(2): 242-249. [13] Yamanaka K. A novel neutral point potential stabilization technique using the information of output current polarities and voltage vector[J]. IEEE Transactions on Industry Applications, 2002, 38(6): 1572-1580. [14] 宋文胜, 冯晓云, 蒋威. 一种单相三电平中点钳位式整流器的SVPWM控制方法[J]. 电工技术学报, 2007, 22(7): 69-73.
2011, Vol. 26 
