Performance analysis of multilevel inverters using variable switching frequency carrier based PWM techniques

Abstract

In this paper, various pulse width modulation techniques are proposed, which can minimize total harmonic distortion and enhance the output voltages in five-level inverters. Multilevel inverters are important for power electronics applications, such as flexible AC transmission systems, renewable energy sources, uninterruptible power supplies and active power filters. Two methodologies adopting phase disposition and phase opposition disposition pulse width modulation concepts are proposed in this paper. These methodologies are divided into two techniques: sinusoidal pulse width modulation which minimizes total harmonic distortion and sinusoidal pulse width modulation with zero sequence signal which enhances the output voltage. FPGA has been chosen to implement the pulse width modulation due its fast prototyping, simple hardware and software design. The simulation and experimental results are presented.