A new boost switched capacitor multilevel inverter using different multi carrier PWM techniques

Abstract

In this paper, a new boost switched capacitor multilevel inverter is proposed. Two structures: a switched capacitor circuit & a two level (full bridge) inverter are connected in cascade. The proposed inverter outputs a larger output voltage than the input voltage. The inverter can be smaller than the conventional two-stage inverter, which consists of boost converter and a full bridge inverter. Number of switching devices used in the circuit is reduced as compared to the conventional cascaded multilevel inverter of same configuration. The multilevel dc output voltage of the switched capacitor circuit is the input voltage of the classical full bridge inverter, resulting in a staircase output voltage waveform. Such a multilevel waveform is close to a sinusoid; its harmonic content can be reduced when compared to the conventional multilevel inverter by using the pwm control strategy. The proposed inverter is driven by different multi carrier based techniques like PDPWM, PODPWM & APODPWM and total harmonic distortion (THD) of each type is compared. The simulation model is done using MATLAB 7.9/ SEVTULINK package & results are shown.