Dear Shrinivas,

Actually in Selective Harmonic Elimination (SHE), harmonics are not removed but just are replaced. It means that when you calculate the angles using SHE equations and some numerical method techniques, the solutions are approximated values. Since you are not attenuating the particular harmonic(s) but only eliminating it, hence the energy of lower order eliminated harmonics is transferred to other higher order harmonics. And this is a major disadvantage of this technique.

based on the mathematical methods only

Dear Prabhu,

can you please provide the reference. I want to goDera through it. 

Dear Sharma,

yes I know it's based on mathematical method. But how ?

SHE can be achieved through the modulation technique.

Dear Ramasamy,

cam you please elaborate, explain how exactly modulation removes harmonics 

I will share with you the attached file, it may help you to inderstand the concept.

However, you should carefully review your application and the required response time and modulation index control requirements, as the complex calculations as well as the limited modulation index control are the main issues in SHE.

Dear Elgenedy,

Thanks for your reference file, i went through it. it does not  explain about the actual working of SHE.

if it is possible you may go though the video lectures by g. narayanan on nptel. he has explained this concept in detail

if this question still alive, we can discuss in more details the SHE implementation and practical concepts.