An Improved Space Vector Modulation Strategy with Optimized Switching Sequences for Reduced Current THD

This paper presents optimized Space Vector Modulation (SVM) switching sequences for three-phase Voltage Source Inverter (VSI)-fed induction motor (IM) drives, focusing on harmonic suppression and switching loss reduction. With the growing demand for high-performance motor drives in industrial applications, advanced Pulse Width Modulation (PWM) techniques play a crucial role in minimizing current distortion, enhancing DC bus utilization, and improving inverter efficiency. The study evaluates conventional SVM, its switching sequences, bus clamping techniques, and enhanced bus clamping strategies. While SVM outperforms sine-triangle PWM in flexibility and performance, conventional implementations do not fully exploit its benefits. In addition, introducing optimized switching sequences that redistribute active vector durations, SVM gains additional degrees of freedom unavailable in carrier-based methods. Experimental results demonstrate that strategic bus clamping significantly reduces line current Total Harmonic Distortion (THD). At full-load operating conditions, the proposed switching sequences achieve a current THD of 5.1%, which is lower than that achieved with conventional SVM switching sequences. Furthermore, the impact of different switching patterns on inverter switching losses is analyzed. A comparative assessment of harmonic spectra and THD levels validate the effectiveness of the proposed sequences, offering improved efficiency and power quality for VSI-fed IM drives.