Power quality enhancement in high power multi-level drives

A new approach to improve the power quality of high power medium voltage multi-level drives is presented. A modular transformers strategy in conjunction with modular power electronics cubes is developed. By applying this technology, the input current harmonics decreases to well below the requirement of IEEE 519-1992 while the amount of capacitance installed in the drive is significantly decreased. Besides by employing modular transformers technology and efficient cooling, power density of the drive is increased by 15%. The input power factor of drive is also improved. This paper details the new approach, analyses and test results.