Constant switching frequency control of a three phase PWM boost rectifier under extreme unbalanced conditions

摘要

According to the new standards (grid codes) Renewable Energy Sources are required to remain connected to the grid during short grid disturbances and to guarantee high power quality, which imposes severe demands upon the grid-side converters. This paper presents a novel current control method for the PWM boost type rectifier under extreme unbalanced operating conditions. The proposed method provides complete elimination of low order harmonics in line currents and output voltage under generalized unbalanced input voltages and impedances. In addition, the input power factor can be adjusted in a wide range. Moreover, due to constant switching frequency, line current harmonics are concentrated in the high frequency region, thus facilitating filtering. Analysis of switching stress and line current distortion carried out on a simulation model demonstrates the effectiveness of the proposed algorithm.