Comprehensive analysis of neutral point clamped inverter

Abstract

Three-level Neutral-point-clamped inverters are increasingly applied in high power and high voltage application. They allow the use of lower voltage devices and provide reduced output voltage total harmonic distortion. However, the traditional modulation scheme causes a low frequency oscillation of the neutral-point voltage (especially for high modulation index and low power factors loading) that increases the voltage stress on the device and capacitors, and the need for larger dc-link capacitors. In order to keep the neutral-point voltage balance, many researchers have proposed several modified scheme. In this report, a comprehensive analysis and comparison for four schemes (Radial State SVM, Nearest Three Virtual SVPWM, 3D SVM and traditional SVM) were performed with computer simulation.