Cascade rectifiers and multi levels applied to the improvement of the quality of electric energy

In this paper, an analysis of the potentialities of the 6, 12 and 24 pulse cascade rectifiers in eliminating harmonics injected in the electric network is treated. Given the dimension, the number of the required transformers and the high cost of the cascade rectifiers, an alternative consisting in multilevel rectifiers with PWM control are proposed as an alternative. These can generate quasi-sinusoidal currents leading to a reduction of the harmonic distortion thanks to the high number of voltage levels. The obtained results are very promising.