A study of six-phase diode rectifier with tap-changer interphase reactor

In power systems with simultaneous AC and rectified loads, it is important to eliminate effectively the AC current harmonic distortion. This paper presents a detailed analysis of six-phase diode rectifier system with tap-changer. Mathematical models are established under reasonable assumptions, considering commutation processes or not. AC current and output DC voltage waveforms are provided via analytic method. Furthermore, a Fourier series expansion of the AC current is presented. According to the theoretical and experimental results, the influential factors of current harmonic distortion are examined and the optimum turn ratio of the tap-changer is derived. Achievements in this paper are a most important technical guidance for the design of the scheme.