A Frequency-domain Model of Common-Mode and Differential-Mode Sources in Three Phase Diode Rectifier Systems

This paper develops a frequency domain model to estimate the spectra of the conducted emissions caused by three phase diode rectifiers. Based on Fourier analysis, the common and differential mode excitation sources generated by the grid side voltage including harmonics are derived in the frequency domain. The Non-linear behaviour of three phase rectifiers and the influence of input harmonics are investigated. Calculated emission spectra are validated with time-domain simulations and laboratory measurements. The results show a good agreement. The proposed method allows emission spectra to be predicted without a specialist circuit simulators and the results can also be used for further study of filter design and defining new harmonics standards.