Perturbation estimation based nonlinear adaptive control of VSC flexible excitation system

A new type of flexible excitation system (FES) is proposed by using fully-controlled power electronic devices such as IGBTs to replace the half controlled in conventional static system, which has merit independent control rotor angle and terminal voltage synchronous generator. This paper proposes nonlinear adaptive (NAC) strategies for generator with FES a single machine infinite bus system. External disturbances uncertainties all parameters well modelling are defined lumped perturbation terms estimated observers or state observer. The used compensate real perturbations achieve model-independent robust NAC. Merits against effectiveness NAC scheme accurate model based multi-variable feedback linearisation verified via small-signal stability analysis simulation studies. results have shown that can superior performance less states during three-phase short circuit better robustness parameter uncertainties, compared linear control.