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This paper offers novel non‐linear control of a doubly fed induction generator (DFIG) and unified power flow controller (UPFC) for transient stability increment with transient energy function (TEF) and sliding mode observer in a power system. First, the TEF technique is considered for the damping control in a power system with a synchronous generator (SG), DFIG, and UPFC, and then the controller time‐derivative signals are estimated by a second‐order sliding mode observer. The importance of the issue is in the employ of a complete UPFC model. Also, a one‐axis model is used for DFIG that is similar to the SG model. Another characteristic of the novel non‐linear technique is robust versus system topology changes and variable time delay of the control signals. To evaluate the performance of the novel non‐linear control method for increment transient stability, simulation studies are performed on a two‐machine connected to an infinite bus (TMIB), the IEEE 9‐bus, and the New England Standard 39‐bus power system. The results determine that the novel non‐linear control method decreases the first swing of fluctuations admissibly and enhancement stability margins considerably.

This paper offers non‐linear control for enhancing the transient stability in power systems containing a photovoltaic (PV) and doubly fed induction generator (DFIG) by transient energy function (TEF) method and finite‐time observers. At first, the TEF method is utilized to enhance the transient stability in a power system containing a PV, DFIG, and synchronous generator (SG) by constructing a hybrid Lyapunov function. Then, the derivative terms in control are estimated with finite‐time observers. The main contribution of the research is the application of the TEF technique in the transient stability evaluation of a power system consisting of PV, SG, and DFIG. Another innovation of the research is the simultaneous control of DFIG and PV, whose uncertain parameters are estimated with the use of finite‐time observer. The proposed non‐linear control scheme is robust against changes in the configuration of the power system. In order to show the capability of this control scheme, time domain simulations are performed on the IEEE 9‐bus, and the NEW ENGLAND Standard 39‐Bus power system. Using the obtained result, some comparisons are made with the back‐stepping control scheme to clarify the superiority of the proposed method. The comparisons show that the proposed non‐linear control scheme can properly provide extra damping to reduce the first‐swing fluctuations in less time.