Line‐side behaviour of three‐phase diode rectifiers with reactance smoothing

This paper describes the line‐side behaviour of three‐phase diode rectifiers depending on AC‐ or DC‐side smoothing reactances. The special case of DC reactance only is investigated analytically by the aid of switching functions, showing basic dependencies for neglected commutation effects. The generalized case of AC‐and DC‐side reactances must be solved iteratively, whereby a significant reduction of the evaluation effort is achieved by a set of analytical equations. All results are presented in uniform diagrams to allow a comparison of both reactance locations. It results that DC‐side smoothing is advantageous with respect to the behaviour of the fundamental and 5th line‐current harmonic, whereas A C‐side reactances are leading to lower amplitudes for all other harmonics. In case of DC smoothing reactance, even small AC reactances influence the line‐side behaviour significantly.