Nonlinear Robust Voltage Control for Synchronous Generators
Ruan Yang1, Yuan Rongxiang1, Wan Li2, Zhao Hongsheng3
1. Wuhan University Wuhan 430072 China 2. Hubei Electric Testing & Research Institute Wuhan 430077 China 3. HBEPC Economic and Technology Research Institute Wuhan 430077 China
Abstract:Most nonlinear excitation control methods depend on the operating point of power system and can’t assure voltage regulation accuracy of synchronous generators. For this reason, a nonlinear robust voltage control strategy is proposed in this paper. For a synchronous generator connected to power network through a transformer, the mathematical model is transformed into a uncertain linear system with the state variables of deviations of generator terminal voltage, rotor speed and generator active power output. And then a nonlinear voltage controller is designed utilizing a linear matrix inequation(LMI) based robust control theory. Compared with the existing controllers, the proposed controller assures voltage regulation accuracy and adapts to system parameters and operating points. And the controller doesn’t need to be respectively designed for single-machine-infinite-bus system and multi-machine power system. Besides that, neither rotor angle nor any variable’s differentiation or integration needs to be measured for the controller. Detailed tests were conducted by PSCAD/EMTDC for a single-machine-infinite-bus system and WSCC 4-machine power system respectively, and simulation results illustrate good performance of the proposed controller.
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