In the case of single-pulse width modulation, the width of the pulse is adjusted to reduce the harmonic. In general, the RMS value of the amplitude of harmonic voltage of a single pulse modulated wave is given by.

$$E_{L n}=\frac{4 E_{\mathrm{dc}}}{\sqrt{2} n \pi} \sin \frac{n p}{2}=\frac{2 \sqrt{2} E_{\mathrm{dc}}}{n \pi} \sin …