An Optimum Hybrid SVPWM Technique for Three Level Inverter

Three level voltage source inverter (VSI) is widely used in high power medium voltage drive applications. This paper presents a top to bottom global optimization approach based on space vector pulse width modulation (SVPWM) technique. The proposed approach implements an optimization method by constructing the reference voltage from the equivalent two level inverter space. The proposed approach achieves the capability to associate a specific switching sequence to a sample point in a sector with a single switching and optimizes the total harmonic distortion (THD) of three level VSI. In this work a new parameter is introduced to incorporate the heterogeneous switching sequences of SVPWM technique. This provides a common platform to compare the measure of contribution of heterogeneous switching sequences of SVPWM towards THD. The proposed SVPWM technique is implemented on a low cost PIC microcontroller (PIC18F452) and verified experimentally with a 2 KVA three phase three level insulated gate bipolar transistor (IGBT) based VSI. The analytical and experimental results of the optimum switching sequences in the three level inverter configuration are demonstrated.