Imaginary Coordinate System Based Space Vector Pulse Width Modulation of a Cascaded H-Bridge Multilevel Inverter

This paper mainly focusses on the imaginary coordinate transformation technique based Space Vector Pulse Width Modulation (SVPWM) of a multilevel inverter. Imaginary coordinate system based SVPWM involves simpler calculations. It does not use any look-up table or trigonometric calculations and eliminates redundant vectors. The SVPWM scheme based on the imaginary coordinate system proposed in this paper works on minimum device switching frequency which in turn reduces the switching loss, thereby increasing the overall efficiency of the inverter. A step-by-step implementation of an imaginary coordinate transformation technique based pulse width modulation of a cascaded H-Bridge multilevel inverter is detailed here. The proposed technique is simulated for a five-level inverter and validated using MATLAB/Simulink. The simulation results show that the proposed technique gives better performance when compared with the conventional SVM techniques. The proposed technique is perfectly general and can be extended to any n level multilevel inverter.