Impedance-Based Stability Analysis of Grid-Tied Photovoltaic System With Superconducting Magnetic Energy Storage System

As the deployment of superconducting magnetic energy storage (SMES), the characteristic of grid-tied photovoltaic system becomes more complicated. However, existing research of the grid-tied photovoltaic system takes no account of the effects of SMES system. Hence, an investigation is made on the effects of digital control delay of SMES converter on the stability of system in this paper. The modelling of grid-tied photovoltaic system is proposed based on impedance modelling method, where the digital control delay of SMES converter system is considered. It is shown that the digital control delay of SMES converter deteriorates system stability and even leads to instability. Meanwhile, the stable grid-connected capacity of photovoltaic system is also reduced due to the weaken of system stability. The simulations are performed to validate that SMES's digital control delay has a significant impact on system.