PROJECT TITLE :

Synchronized Space-Vector PWM for Three-Level VSI With Lower Harmonic Distortion and Switching Frequency

ABSTRACT:

A completely unique synchronized house-vector pulsewidth modulation (SSVPWM) strategy is proposed for three-level inverters, which focuses on improving the output waveforms whereas reducing the device switching frequency. The modulation index m is segmented in linear modulation region reasonably, and the switching sequences are designed at each segmentation independently. The sequences for 2 reference vector distribution modes are designed, respectively, that ensure the synchronization and symmetry in output waveforms and also the minimization of switching frequency. Then, the optimal sequence at each segmentation is chosen from the 2 sequences (akin to the two modes) in terms of the weighted total harmonic distortion (THD) of line voltage. The proposed strategy is verified through simulation and experiment on a constant v/f open-loop induction motor drive, and also the results show that each line voltage weighted THD and no-load stator current THD will be significantly reduced compared to traditional SSVPWM (CSSVPWM) and house-vector-based synchronized discontinuous PWM (SDPWM) in linear modulation region. Moreover, at a bound reference vector number, the switching frequency will be reduced by thirty three.3p.c compared to CSSVPWM and thirteen.3p.c to SDPWM. The proposed strategy will additionally be implemented within the overmodulation region.