8122 Harmonics in Sinusoidal PWM

The inverter output phase voltage contains harmonics that are of odd multiples of the carrier frequency fc(i.e.,fc, 3fc, 5/c,...).The waveform also contains sidebands centered around multiples offcand given by where k1 +k2 is an odd integer. The harmonic frequency centers are at kffor odd integers of k1, while the sidebands are symmetrically located without a center for even integers of ki. Note that the magnitudes of band frequency harmonics decrease rapidly with increasing distance from band center. The harmonic frequency components for k 1 = 1 and k1=2, along with the bandwidth, are shown in Figure 8.9. The bandwidth of harmonics is the range of frequency over which the harmonics are considered dominant. The frequency bandwidth increases with m. The dominant harmonics among the sidebands are at frequencies (p±2f and (2p± 1f.

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