Design space exploration of optimized hybrid SVPWM techniques based on spatial region for three level VSI

Abstract

The performance of a multilevel inverter depends upon design and selection of an appropriate modulation technique. Space vector pulse width modulation (SVPWM) technique offers more flexibility than other pulse width modulation (PWM) techniques. However, conventional SVPWM technique becomes more complex for multilevel inverter because of increased number of space vectors and redundant switching states. This paper presents a design space exploration method of hybrid SVPWM techniques for three level voltage source inverter (VSI) to reduce total harmonic distortion (THD) and switching loss over wide linear modulation range. A new parameter Harmonic Loss (product of weighted total harmonic distortion factor of the line voltage (Vwthd) and normalized switching loss) is introduced as an objective function, and a spatial region identification algorithm is proposed to determine the optimized switching sequences for hybrid SVPWM technique. Two optimized hybrid SVPWM techniques are proposed based on the optimized switching sequences for three level VSI. The proposed hybrid SVPWM techniques are implemented on a low cost PIC microcontroller (PIC 18F452) and applied on an experimental prototype of three phase three level VSI with an induction motor as load. The experimental results are demonstrated to validate the performance of the proposed hybrid SVPWM techniques.