Abstract：The uniform spectral characteristics are achieved in the whole frequency interval for the randomized switching frequency PWM method. However, the synchronous change of sample frequency and switching frequency makes the filter design complex, meanwhile the digital realization of engineering becomes difficult as the gain of controller and modulator vary with the sample frequency. A novel strategy of dual randomized modulation is presented by which the sample frequency could keep unchanged. The delay time of next pulse output is calculated in current sampling interval with variable delay technique. The randomized switching period is formed with the interval of two output pulses. Zero vectors are randomized with the sample frequency and the average switching frequency equals to sample frequency with some constraint. Analysis and experiment indicate that the method has intensive commonality and good spectral characteristic, which can be realized only by software without modifying the hardware and radiating design.
王庆义, 邓歆, 刘洋, 尹泉. 一种零矢量-变延时随机PWM方法[J]. 电工技术学报, 2009, 24(12): 132-136.
Wang Qingyi, Deng Xin, Liu Yang, Yin Quan. A Method of Zero Vector and Variable Delay Randomized PWM. Transactions of China Electrotechnical Society, 2009, 24(12): 132-136.
[1] Stankovic A M, Verghese G C, Perreault D J. Analysis and synthesis of randomized modulation schemes for power converters[J]. IEEE Transactions on Power Electronics, 1995, 10(6): 680-693. [2] 王斌, 李兴源, Drissi K K. 双随机调制技术及其功率谱密度特性分析[J]. 中国电机工程学报, 2004, 24(4)：97-101. [3] Hui S Y R, Sathiakumar S, Sung Ki-Kwong. Novel random PWM schemes with weighted switching decision[J]. IEEE Transactions on Power Electronics, 1997, 12(6): 945-952. [4] 王斌, 李兴源, 王颢雄, 等. 基于马尔可夫链的双随机PWM技术研究[J]. 电工技术学报, 2005, 20(6): 16-24. [5] Trzynadlowski A M, Borisov K, Li Yuan, et al. A novel random PWM technique with low computation overhead and constant sampling frequency for high- volume low-cost application[J]. IEEE Transactions on Power Electronics, 2005, 20(1): 116-122. [6] Schulz S E, Kowalewski D L. Implementation of variable-delay random PWM for automotive applications[J]. IEEE Transactions on Vehicular Technology, 2007, 56(3): 1427-1433. [7] Bech M M, Blaabjerg F, Pedersen K. Random modulation techniques with fixed switching frequency for three-phase power converters[J]. IEEE Transactions on Power Electronics, 2000, 15(4): 753-761. [8] 陈颖, 叶芃生. 基于DSP的RPWM技术[J]. 上海交通大学学报, 1999, 33(10)：1298-1300. [9] Hui S Y R, Oppermann I, Pasalic F, et al. Micropro- cessor-based random PWM schemes for DC-AC power conversion[J]. IEEE Transactions on Power Electronics, 1997, 12(2): 253-260. [10] Kirlin R L, Bech M M, Trzynadlowski A M. Analysis of power and power spectral density in PWM inverters with randomized switching frequency[J]. IEEE Transactions on Industrial Electronics, 2002, 49(2): 486-499. [11] Trzynadlowski A M, Bech M M, Blaabjerg F, et al. Optimization of switching frequencies in the limited- pool random space vector PWM strategy for inverter-fed drives[J]. IEEE Transactions on Power Electronics, 2001, 16(6): 852-857. [12] 马丰民, 吴正国, 侯新国. 基于统一PWM调制器的随机空间矢量调制[J]. 中国电机工程学报, 2007, 27(7)：98-102. [13] Borisov K, Calvert T E, Kleppe J A, et al. Experimental investigation of a naval propulsion drive model with PWM-based attenuation of the acoustic and electromagnetic noise[J]. IEEE Transactions on Industrial Electronics, 2006, 53(2): 450-457.
2009, Vol. 24 
