Voltage and current dynamics cancellation of weak-grid-tied grid-following inverters for maximum transferable power improvement

The maximum transferable power (MTP) of phase-locked loop (PLL)-based grid-following inverters can be constrained by weak grid conditions. This article aims to develop a robust method for improving MTP by canceling the voltage and current dynamics induced by the PLL. To this end, this article identifies the contributions of the current control loop and PLL, both individually and in interaction, to the inverter's admittance using the admittance decomposition technique. Based on these insights, the non-passive effects of current control loop and PLL-induced dynamics are mitigated through a specifically designed point-of-common-coupling voltage feed-forward loop. The effectiveness of this developed method for canceling voltage and current dynamics is validated through admittance and eigenvalue analysis, complemented by simulation studies and experimental results.