Research On Nonlinear Control Strategies For Statcom

With the continual development of the reform of electric power and the increase of the various power loads in China, more and more requirements of power quality are needed, so the reactive power compensation becomes increasingly important in the power system. FACTS (Flexible AC Transmission System) provide a very effective means for the security, economic benefits, reliability and high-quality operation of the modern power system. As an important member of the FACTS, the STATCOM (Static Synchronous Compensator) is an important device in implementing dynamic reactive power in power electronic disciplines currently. This paper studies the nonlinear control strategy of the STATCOM.In the theory respect, the influence of the reactive power in the power system, the meaning of the reactive power compensation, FACTS devices and research status of the STATCOM are introduced firstly. Secondly, the STATCOM working principle and current reactive detection method commonly used are introduced in detail. Lastly, three kinds of nonlinear control therories and the current control mathods are introduced; the passive control theory is introduced with its related concepts, Lyapunov Stability Theorem, the passive system, Euler-Lagrange system and EL controller; inverse theory is introduced with its related concepts, the linearization method in SISO system and decoupling and linearization in MIMO system; variable structure control theory is introduced with its related concepts, design process of variable structure controller and the jitter supressed methods.In the respects of mathematic model and control, the mathematic model of the STATCOM and the Single-Machine-Infinite-Bus-System involved STATCOM are built. The EL controller is designed for the device-level STATCOM based on the passive control theory; the variable structure controller is designed for the Single-Machine-Infinite-Bus-System involved STATCOM based on the variable structure control method based on the inverse system theory and. Finally, verify the validity and superiority of the nonlinear controllers through the analysis and comparisons between the Matlab simulation results of the designed controllers and the other controllers.