Harmonic Analysis of Three-Phase Diode Bridge Rectifiers Under Unbalanced and Distorted Supply

Developing an effective harmonic power flow tool requires fast and accurate calculations of the harmonics generated by the nonlinear elements. This paper presents a time-domain-based method for obtaining all steady-state characteristic and noncharacteristic harmonics generated by three-phase diode bridge rectifiers, under unbalanced and distorted supply. The developed model is generic and able to address both continuous- and discontinuous-conduction modes with a single formulation. By introducing a virtual resistance on the rectifier's DC side, the model is extended to accommodate any DC-side filter. Further, a unique analytical Jacobian matrix is developed to guarantee a quadratic convergence for the iterative part of the proposed method. The effectiveness of the proposed method for harmonic analysis is confirmed through a comparative evaluation with time-domain simulations using PSCAD/EMTDC.