Time-to-Frequency Domain SMPS Model for Harmonic Estimation: Methodology

The amount of home appliances based on Switch Mode Power Supply (SMPS) systems has increased over the last years. Thus, the harmonic analysis of these loads is useful for the assessment of current distortion in low voltage distribution systems. However, an assessment considering the diversity and attenuation effects represents a challenge on harmonic modeling. This paper proposes a method (T2FDM) to transform SMPS Time Domain Models (TDM) into Frequency Domain Mod els (FDM) in order to estimate the input current waveforms when the amplitude, phase angle and distortion of the supply voltage varies (e.g., voltage regulation) around some operating point. The T2FDM provides the Admittance matrix, which is suitable to assess the impact of household loads with lower computational cost. The method is based on the use of Polar plots Fingerprints computed from TDMs and not from a large set of measurements. The results from T2FDM, FDM and TDM are compared against laboratory measurements via the computation of error performance metrics. The study shows that the methodology is appropriate to compute accurate and efficient FDMs from a TDM and a small set of measurements.