Space vector pulse-width modulation scheme for multilevel voltage inverters with duty cycle calculation based on relative vector distances

摘要

In this study, a control scheme for multilevel inverters is formulated employing space vector pulse-width modulation. The notable formulation bases the duty cycle calculation on relative distances among constructive vectors provided by the line-neutral voltage levels of the converter topology. Furthermore, in order to locate the control vector (or reference vector) properly, Clarke transformation of instantaneous line-neutral voltages is employed. In this way, calculations of duty cycles are simplified, closed- and open-loop operations have similar approaches and linear and over modulation operations are performed with minimal variations. Also, this approach eliminates the use of trigonometric functions in order to reduce memory demands and computational capacity. The scheme is tested on a 7seven-level inverter with cascaded H-bridge topology using real-time simulation.