3-Level Neutral-Point Clamped Inverters Using Multi Carrier Pulse Width Modulation for FACTS Applications

In this paper, a novel technique used to keep the voltage across the dc split capacitors of neutral point clamped inverter using multi carrier pulse width modulation and also compensate the reactive power. It can reduce the harmonics without any changes in inverter output. Multi carrier pulse width modulation is controlling the neutral point voltage at full modulation index. It require compensation loop because it does not deliver the natural voltage balancing. The voltage is balanced under all operating conditions. This results in smaller harmonics, but on the other hand it has more components and is more complex to control. In this paper, different three level inverter topologies and SPWM technique has been applied to formulate the switching pattern for three level inverter that Minimize the harmonic distortion at the inverter output. Simulation result has discussed.