The increase in power electronic (PE) devices has caused a wide penetration of Switch Mode Power Supply (SMPS)-based loads, which include single-phase full bridge rectifiers. Therefore, potential problems on power quality may also increase. Thus, the modeling and harmonic analysis of SMPSs are useful to assess the contribution on current distortion and the impact of several of these loads connected on a low-voltage network. However, an assessment of multiple loads considering the interactions between them and the equivalent system impedance together with the voltage distortion and the harmonic phase angle dispersion represents a challenge on harmonic modeling. This paper proposes the use of a SMPS Time Domain Model (TDM) to compute synthetic signals which are used to fit a Frequency Domain Model (FDM) that allows the estimation of the harmonic current distortion with lower computation cost than a Time Domain simulation. Moreover, this paper proposes a probability approach to compute this FDM rather than a regular deterministic approach. The proposed approach is based on the signals that more likely to be present over a time and to comply with the limits proposed by distortion standards or possible phase angle operation points. The FDMs results from the proposed and regular approaches are compared with respect to the TDM through the magnitude relative error and phase angle absolute error on MATLAB platform. The study reveals that despite the approaches have the same computational cost, the proposed approach is more effective than the regular approach for computing accurate FDMs for an SMPS.
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