Multi-frequency Small-Signal Model of Single Phase Diode Rectifier

This paper addresses the problem of accurately modeling diode-based rectifiers by linearizing the switching function dynamics caused by AC side perturbations. The critical challenge is infeasible to directly linearize the switching functions due to a non-derivative point in the AC current. To overcome this limitation, we propose a novel technique that establishes a linear correlation between the switching perturbation and the current perturbation using the harmonic balance method. By considering the internal dynamics of the switching process, our approach builds a small-signal model using the harmonic state space (HSS) method, enabling a more precise representation of the rectifier’s low-frequency AC impedance. The effectiveness of our approach is validated through frequency scanning in electromagnetic transient (EMT) time-domain simulations, demonstrating the enhanced accuracy of the small-signal model.