Maximum Transferred Power Constraints Analysis of the Grid-Tied VSC Based on the Modified Transfer Function

This letter establishes the constraints identification index of grid-tied voltage source converter (VSC) maximum power transfer points. The phase-locked-loop linearization model is firstly modified to diminish the instability identification errors of the parameter design-oriented transfer function. Based on the proposed transfer function, the dynamics of grid-tied VSC can be analyzed from system and control parameters, respectively. Subsequently, based on the maximum injected current, the constraints identification index <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K</i> is deduced to identify the impact of control dynamics on stability. The maximum transferred power is limited by small-signal control dynamics when <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K</i> ≥ 1, while it is restricted by the system Jaccobi-matrix and control dynamics can be neglected when <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K</i> < 1. Frequency and time domain simulations are applied to show the effectiveness of the proposed analysis.