A multilayer loop gain-based eigen-sensitivity method for oscillation diagnosis of converters-dominated system

Eigen-sensitivity is a useful tool in revealing the root cause of the oscillation instability and guiding its suppression. For the converters-dominated system, loop gain-based eigen-sensitivity (LGES) can be helpful, providing sensitivity information from the frequency domain perspective. However, the existing LGES is still scant in two aspects: eigen-sensitivity indices are bound up with frequency domain characteristics that does not necessarily point to the stability as that of the time domain state-space eigen-sensitivity; a systematic LGES framework with the participation factor (PF), component and parameter sensitivity is missing. These two factors hinder the LGES method on proper and comprehensive evaluation of stability effects. To this end, this paper proposes a multilayer LGES method directed to oscillation modes (i.e., time-domain eigenvalues), and a full set of sensitivity indices are established. The link from the eigen-sensitivity of frequency domain to that of time domain is revealed, from which it is shown how the proposed method can facilitate the parameter tuning-guided oscillation suppression. The effectiveness of the proposed method is validated using a generic AC/DC converter-based system.