A time-domain method for calculating harmonics produced by a power converter

In general, power converters are nonlinear and time varying devices. Power electronic converters contribute significantly to the harmonic pollution of transmission systems. Being able to predict accurately the values of harmonics injected by the converters is essential for the power system planning and studies. Power converters can be classified into two types-line-commutated and force-commutated converters. In this paper, a unified time-domain method is presented to show how the harmonics produced by a line-commutated or a forced-commutated circuit can be easily calculated, provided that the switching times are known. All the results are validated with PSCAD/EMTDC.