Large Signal Stability Analysis of a Hybrid AC/DC Microgrid With a Cascaded Control Inverter

The large signal stability analysis of a hybrid AC/DC microgrid based on a grid-connected inverter with cascaded control is discussed. The impacts of the connected inductor, capacitor, and the control parameters of the inverter on the DC link stability region are analyzed. To achieve these analyses, a dynamic model of the microgrid with the cascaded control inverter is first developed. A Lyapunov large-signal stability analysis tool is then applied to estimate the domain of attraction, which is the asymptotic stability region. Results show that DC side capacitor, the AC side grid filter, as well as the control gain, will have different influences on the stability regions of the DC link voltage. High fidelity simulations through PLECS are successfully applied to verify the asymptotic stability regions estimated from the Lyapunov large signal analysis method.