Harmonic elimination in multilevel inverters using evolutionary computation techniques

Abstract

The modern electrical power generation and distribution systems are moving in a direction where the renewable energy sources are receiving importance in the recent years. In renewable energy generation, Power electronic converters play a major role in converting power from the available form to the required form. Inspite of that, the inverters using the discretely switched power electronic switches for DC to AC conversion does not directly deliver a smooth sinusoidal wave. Apart from the conventional three level inverters, to synthesize better power quality AC output, Multi-Level Inverters (MLI)are used to obtain more sinusoidal output with reduced harmonics and THD, so that they require smaller passive filters. Amid of the standard configurations of MLIs, Cascaded H-Bridge MLI is most acknowledged topology due to its ease in the variation of voltage levels, unsophisticated design, low dv/dt, lesser switching stress across the devices. Also, to overcome the limitations of passive filters such as bulky passive components for filtering lower frequencies, risk of resonance problems, Pulse Width Modulation (PWM) based inverters are used to produce a near sinusoidal wave with minimum lower order harmonics. Hence, it needs minimum filtering requirements to remove higher order harmonics. Sinusoidal PWM (SPWM), the Space Vector PWM (SVPWM) are the known types of PWM schemes belong to the high switching frequency category, hence high switching losses newline