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This paper deals with the design of robust regulation for both angular speed stability enhancement and voltage in synchronous generator machines with an excitation control system. The designed controller is based on the block control technique combined with a sliding-mode (SM) control approach. The block control is used to design a nonlinear sliding manifold with the desired stability property. In order to attenuate the chattering effect which can appear in the presence of the exciter's unmodeled dynamics, a high-order SM algorithm and a robust exact differentiator are employed. The efficiency of the proposed controller, i.e., robustness and high accuracy, is verified via simulations.

The dynamics of the most of the industrial plants (for example electric power system, electromechanical system, electro-hydraulic system and so on) are highly nonlinear and, moreover, include actuator dynamics which increase the relative degree of the complete system. To stabilize the plant dynamics it is naturally to applied some feedback linearization (FL) technique: block control [18], backstepping [14] or input-output linearization [11], since the model of these plants can be presented in the nonlinear block controllable form or (the same) strict-feedback one. All these control techniques require to calculate the time derivatives of the plant dynamics vector fields (Lie derivatives), results in a computationally expensive control algorithm, and moreover, the closed-loop system is susceptible to plant parameter variations and disturbances. To simplify the control algorithm the actuator fast dynamics are usually skipped, and to overcome the robust problem the sliding mode (SM) control [25] in combination with FL technique [18], [17] can be can be applied. However, the presence of the actuator unmodeled fast dynamics can destroy the desired behavior of the SM control systems causing lost of robustness and accuracy and provoking the chattering effect [25], [8]. Therefore, the problem of control design for the systems with unmodeled actuator dynamics becomes to be a big challenge.

The synchronous generators have a natural different time scale dynamics. That is why for modeling and control design in such systems the methods of singular perturbations are widely used. In this paper the possibilities of sliding mode control design for synchronous generators are analyzed. With this aim the concept of singular perturbation is revised in order to use it for relay control system with a discontinuous slow-motion integral manifold. Obtained results are used for variable structure control of synchronous generator.

The synchronous generators have a natural different time scale dynamics. That is why for modeling and control design in such systems the methods of singular perturbations are widely used. In this paper the possibilities of sliding mode control design for synchronous generators are analyzed. With this aim the concept of singular perturbation is revised in order to use it for relay control system with a discontinuous right hand side. The obtained results are used for variable structure control of synchronous generator.