Harmonic-Domain Impedance Modeling and Stability Analysis of Single-Phase Inverters

In hybrid AC/DC grids, a bus conversion system comprising of electromagnetic interference (EMI) filters and bidirectional converters is required to ensure energy transmission between DC and AC buses. However, the cascaded system often introduces additional stability problems, which impede the reliable operation of hybrid AC/DC grids. To solve the problem, this paper investigates the cascaded stability of the bus conversion system in hybrid AC/DC grids, and the input impedance of a single-phase inverter is modeled using the harmonic linearization method. The Middlebrook criterion is utilized to determine system stability. Finally, a simulation model is constructed by Matlab/Simulink to validate the analysis conclusion.