正弦脉宽调制毕业设计外文文献及翻译(编辑修改稿)

正弦脉宽调制毕业设计外文文献及翻译(编辑修改稿)内容摘要：

tiple of 3 is also convenient as then the same trian gular waveform can be used as the carrier in all three phases,leading to some simplification in hardware. It is readily seen that as the where E is the dc bus voltage,that the rms value of the output voltage signal is unaffected by the PWM is strictly true for the phase voltage as triplen harmonic orders are cancelled in the line ,the problematic har monics are shifted to higher orders,thereby making filtering much ,the filtering is carried out via the natural highimpedance characteristic of the load. :SPWM Harmonic Spectra:n=15,m=0. Selective Harmonic Elimination (also called Optimal PWM) Notice that in the SPWM strategy developed above,a large number of switchings are required, with the consequent associated switching the method of Selective Harmonic Elimina tion,only selected harmonics are eliminated with the smallest number of method however can be difficult to implement online due to putation and memory requirements. For a two level PWM waveform with odd and halfwave symmetries and n chops per quarter cycle as shown in Fig 4,the peak magnitude of the harmonic ponents including the fundamental, are given : Here is the magnitude of the harmonic and is the primary switching har monics do not show up because of the halfwave symmetry. The n chops in the waveform afford n degrees of control options are thus possi example n selected harmonics can be option which is used here is to eliminate n1 selected harmonics and use the remaining degree of freedom to control the funda mental frequency ac find theα‟s required to achieve this objective,it is sufficient to set the corresponding h‟s in the above equa。