Dead-time Compensation Strategy of Three Level Inverter Based on FFT

Abstract

Considering the influence on the output voltage and current of the three-level inverter by dead time, voltage drop, opening time, turn-off time of power devices and grid voltage, a mathematical model of three-level inverter is built, based on which a dead-time compensation strategy for three-level inverter based on FFT is proposed. The strategy uses Fast Fourier Transform(FFT) to filter current to determine the polarity of current accurately. The simulation based on three-level inverter shows that the compensation strategy of the dead time can effectively reduce the harmonic content of the output current introduced by the dead time and avoid the zero-current clamping.