Three-phase diode rectifier with low harmonic distortion to feed capacitive loads

In this paper, a new technique for shaping the line current and reducing the total harmonic distortion in a three-phase bridge rectifier, feeding a capacitive load, is presented. Using the topology proposed by Ewaldo et al. (1995), a new control technique has been implemented. The main objective here is to minimise the THD of the line current under different load conditions (20% to 100% of full load). A review of the problems inherent in a bridge rectifier feeding a capacitive load and the possible solutions are first presented. Subsequently, the analysis of the new circuit, and the control technique used are described along with simulation results. Finally the experimental results on a 1.6 kW prototype are presented