Stability analysis method considering impedance coupling of photovoltaic and network-forming MMC (Modular Multilevel Converter)

The invention relates to a stability analysis method considering impedance coupling of a photovoltaic and network-building type MMC, and the method comprises the steps: firstly, accurately building a harmonic state space model of the network-building type MMC, and extracting impedance components with the frequencies of fp-2f1 and fp, thereby effectively achieving the harmonic path analysis; after the harmonic transmission process of the photovoltaic unit and the network-building type MMC is analyzed through a signal flow diagram, the mutual influence between the impedance of the photovoltaic unit and the impedance of the network-building type MMC is accurately described, and it is shown from an analytical formula that the equivalent admittance of the photovoltaic unit contains the impedance element of the network-building type MMC, and the equivalent impedance of the network-building type MMC also contains the impedance element of the photovoltaic unit. Therefore, according to the stability analysis method co