Univariate equation-based SHE-PWM for multilevel inverter

摘要

This article presents a selective harmonic elimination-pulse-width modulation (SHE-PWM) method for cascaded H-bridge multilevel inverters. The concept of volt-second area balancing is applied to estimate the voltage ratings of the dc sources, which provides different voltage ratings of each dc source. The control of output voltage is achieved by varying switching notch created at the centre of each level. This method calculates switching angles in real time easily owing to the usage of univariate equations. A comparison study shows that the proposed method eliminates more harmonics compared with the conventional SHE-PWM methods. Simulation and experimental studies are conducted to validate the performance of the proposed SHE-PWM method.