新型三相SPWM技术的研究

A Novel Algorithm for Implementing High-Efficiency Three-Phase Sinusoidal Pulse-Width Modulation(SPWM)

利用等效面积补偿的方法推出一种新颖的三相 SPWM技术 ,使调制度 1≤M≤ 1 .2 7时输出电压基波幅值和 M仍保持线性调制关系 ;减小了开关次数 ,使损耗下降。采用分段同步调制技术 ,使三相 SPWM相位精度高 ,波形对称 ,有效抑制了高次谐波 ;充分利用专用单片机内部资源 ,使程序简单 ,运行效率高 ,是一种高效能三相

Application of SPWM technology has rapidly become very widespread and its performance should be improved as much as possible. We exploited fully the potential of the new NEC chip uPD78982 to obtain improvement of SPWM performance in three respects: (1) when the modulation ratio M is in the range of 1≤M ≤1.27,the output amplitude of fundamental component still maintains a linear relationship with M ; (2) the phase precision is high and the waveform is symmetrical. (3) the real time capability of our novel algorithm is high. In our novel algorithm, we make use of two methods:(1) the method of equivalent area compensation discussed in detail in this paper;(2) the method of subsection synchronization modulation briefly described in this paper but first adapted by us to suit the requirements of air conditioning. Besides, we point out two additional benefits of our novel algorithm: (1) the reduction of switching times slows down the deterioration of switches and reduces radio frequency interference; (2) high phase precision suppresses quite effectively higher harmonics.