Novel PWM scheme to control neutral point voltage variation in three-level voltage source inverter

This paper proposes a simple PWM scheme which alleviates the neutral point voltage fluctuation problem of the three level inverter applications. The new scheme employs modified version of well known multi-level sinusoidal pulse width modulation (SPWM) scheme. This modification shows a great potential of reducing neutral point voltage fluctuation and retained better sinusoidal shape at the output. This method avoids the requirement of high capacity DC link capacitors, which are unavoidable in most of the present three-level inverter industrial applications. Moreover the new PWM scheme is less complex than most of the other available neutral point clamping control methods