During the interaction between inverters and the power grid or other devices

the wide-band dynamic characteristics and multi-frequency coupling properties of inverters may induce wide-band oscillations within the system

or even simultaneous oscillations across multiple frequency ranges. To investigate this complex oscillation problem

which has received little existing attention

the method of multi-harmonic linearization is adopted to investigate the impedance modeling of inverters considering multi-frequency couplings. This approach aims to establish a theoretical impedance model that comprehensively and accurately reflects the wide-band impedance characteristics of inverters. Based on the generalized Nyquist stability criterion

the wide-band stability analysis is carried out for single-inverter and two-inverter grid-connected systems

and the accuracy of the theoretical analysis results is verified through time-domain simulations. On this basis

the influences of system parameters on wide-band oscillations are analyzed. The research findings indicate that system parameters exert different influences on oscillations within different frequency ranges. Finally

a comparison of the proposed impedance model with other commonly used impedance models is carried out and validated by a hardware experimental platform that is closer to reality

illustrating the accuracy of the research work in this paper.