The phasor method

along with its related concepts

plays a pivotal role in the analysis of AC power systems. However

with the proliferation of renewable energy sources and their fast control

the traditional phasor method faces considerable challenges in analyzing the mechanism of system dynamics. To address this issue

this paper presents a novel approach-the time-varying amplitude/frequency (TAF) phasor method-for the dynamic analysis of AC power systems. Firstly

to provide rational descriptions of AC quantities

this paper begins with investigating the characteristic nature of AC signals in dynamics and recognizes them as TAF signals. Then

complex numbers with TAF are employed to describe these AC signals by drawing on the traditional phasor method. The geometric representation via TAF phasor diagrams is also utilized. The proposed TAF phasor method can effectively characterize universal AC signals in dynamics

which existing methods such as the traditional phasor method and dynamic phasor method could not achieve. Sub-sequently

complex numbers incorporating TAF are utilized to describe these AC signals by drawing on the traditional phasor method. In addition

geometric representations through TAF phasor diagrams are introduced.