Backstepping silding-mode control of nonlinear TCSC System based on adaptive observer

Abstract: This paper proposes new approaches for nonlinear thyristor controlled series compensator (TCSC) controller design. The uncertain parameter and external disturbances are considered for practical implementation in power systems. The control law and the adaptive law are designed separately, which can avoid the oscillation of states caused by the coupling between parameter estimator and system states. The adaptive laws of uncertain parameters are estimated by using adaptive observer. The designed adaptive law can ensure that estimation error converge to zero in finite time. Furthermore, the backstepping control and sliding-mode control method is adopted to derive the control law recursively. By using the proposed method, all the state variables in the TCSC system will theoretically attain stability and eventually converge to desired values. Compared with other algorithms, the oscillation amplitudes of transient responses are reduced by nearly half, and the time of reaching steady state is shortened by at least 12%. The results indicate better performance of the proposed controller in both the transient and steady states.