Switched capacitor multilevel inverter with different modulation techniques

A multilevel inverter is a power electronic device that is used for high voltage and high power application because of its characteristics of generating a sinusoidal voltage based on several DC voltage levels. They give good quality output resulting with lower harmonic distortion in the output. This topology is designed based on switched-capacitor voltage pump technique and the number of output levels is defined by the number of switched-capacitor cells cascaded. Only one dc voltage source is needed and the problem of voltage balancing across the capacitor is avoided as well. A small input voltage can be used to generate a boosted output voltage, by switching the capacitors in parallel and in series. Number of switching devices and other components used in the circuit are reduced, compared to the conventional cascaded multilevel inverters of same configuration. This work also presents the comparative study of various Multicarrier Pulse Width Modulation techniques with Sinusoidal reference modulating signal. Performance factors such as % THD and voltage stress across the switches are measured for different modulation techniques and the results are studied. SPWM method with the different carrier based PWM such as sinusoidal PDPWM, sinusoidal PODPWM, APODPWM, VFPWM, COPWM and Sampling PWM (Symmetrical and Asymmetrical) has been analyzed. The simulations for switched capacitor seven level inverter using different modulation techniques are done with MATLAB/SIMULINK software.