Analysis of passive filters for high power three-level rectifiers

This paper studies passive filters for harmonic reduction in high power rectifiers. The paper presents some of the most important configurations of high power filter employed in medium voltage applications. The paper as well includes the ideal mathematic equations and models for those filters, and then compares the filter performances. In a very broad sense, the addition of some resonant harmonic traps to a conventional third order filter results in good filter adaptation to PWM strategies. The filter evaluation highlights this fact. Simulation of a high power three-level neutral point clamped-NPC rectifier also confirms those ideas. Results comprise a high quality waveform under low switching frequency with reasonable converter operation performance. Experimental results for selective harmonic elimination are included.