System harmonics reduction using multipulse AC fed PWM voltage source inverters

This paper studies the harmonic characteristics of multipulse switching mode power converters in the presence of other harmonic sources. Using an 18 pulse PWM voltage source inverter (PWM-VSI) as an example, it is confirmed through tests and simulation that the current harmonics of multipulse converters are strong functions of AC source voltage harmonics. It is shown that multipulse converters can actually reduce system voltage harmonics, acting practically as harmonic filters for other sources. The paper also discusses the importance of transformer impedance and DC link capacitance for the harmonic performance of multipulse converters.