# 21-40 METODĂ ANALITICĂ PENTRU STUDIUL PUNŢII DE DIODE AVÂND O SARCINĂ COMPLEXĂ

THE DIODE-BRIDGE WITH A COMPLEX LOAD
Commonly, three-phase diode bridge rectifiers are often used to
convert AC input into a DC voltage. It is well known that they generate large
amounts of harmonic currents in DC and AC sides.The paper proposes an
analytical method for calculating the harmonic currents of a three-phase diodebridge
under non-symmetrical supply conditions and with a complex load. We
are considering a three-phase ideal diode-bridge fed by a non-symmetrical
voltage system: ea(x) = Easin(x-x1), eb(x) = Ebsin(x-x2) and ec(x) = Ecsin(x-x3).
Performing those calculations we obtain the Fourier coefficients of serial
development for the harmonic currents on both the DC and AC sides. The
equations for the harmonic currents are derived, taking into account the effects
of the DC and AC side impedances. All the calculations are conducted only by
algebraic calculation with high accuracy. The proposed method can be easily
extended to the harmonic analysis of three-phase thyristor-bridge with nonsymmetrical
supply conditions and a complex load.
Cuvinte cheie: punte de diode, alimentare nesimetrică, sarcină complexă,
analiză armonică
Keywords: bridge diode, symmetrical power, complex task, harmonic
analysis

40 METODĂ ANALITICĂ PENTRU STUDIUL PUNŢII