Variable Structure Control Theory Problems And In Applied Research, In Active Power Line Conditioner

In the 1950s, Soviet researcher Emelyanov first proposed the conception of variable structure control. Furthermore, the theory of variable structure system(VSS) was developed by Utkin and Itkis et al. In the 1970s, the VSS was received extensive attention of many researchers owing to its distinct merits and features. Many researchers deeply studied it from the different aspects with many different mathematic methods. Now the variable structure control (VSC) already becomes a relative independent research branch. Moreover, the theory research and application reported of VSC appeared in the field of state estimation, discrete time system control, time delay control, robust control for uncertain systems, adaptive control, output feedback control and so on.Because of its advantage of robustness and easy realization variable structure sliding mode control has been applied gradually in Active Power Filter. Active Power Filter can resolve electrical pollution, increase the stabilization of electrical power system and ameliorate the quality of electrical power. Different type Active Power Filters can compensate dynamic harmonic of dynamic load electrical current and the volt.In the electrical control the action of power electronic switch changes the structure of electrical circuit, the electrical circuit has character of discontinuity. The control electrical circuit formed by power electronic switch is described as variable structure control system. Thereby adopting sliding mode variable structure control method in power electronic electrical circuit is very apt. In addition sliding mode variable structure control has good robustness, is blunt to the change of system and exterior disturbing. In all sliding mode variable structure control has a good future in the control of power electronic devices.This paper is based on the study actuality of VSC and the new requirements from the practice for the theory of VSC, Active Power Line Conditioner and mathematic model of a traditional servo motor with relay are studied and discussed, at last the research outcomes are given. The main contains are as follows:1. Author bring forward a new variable structure control strategy with fuzzy approach law. For a class of Series-wound Active Power Line Conditioner the design approach law of a new fuzzy integral sliding mode variable structure control is presented. This method adjusts power electronic switch in order to achieve anticipated balance volt, finally makes active power line conditioner not only possess good robustness of variable-structure control and decrease vibration to the most but also increase the steady state precision. Series-wound APLC adopted this control method possesses good dynamic and steady state performance. The system performance is investigated in a computer simulation and the results demonstrate the effectiveness of this control method.2. For a class of Shunt-wound Active Power Line Conditioner, based on analysis of mathematical model of system and target of control, the algorithm of fuzzy variable structure sliding mode control is presented. The control algorithm canavoid complicated calculation of harmonic electric current in traditional control algorithm, and realize the feedback control of electric current. The algorithm is simple and easily implemented. The simulation outcomes show that the control strategy is very effective to Shunt-wound APLC.3. This chapter analyzes vibration of a traditional servo motor include relay with place and time lag, and brings forward fuzzy control scheme, changes the time of control action in the place delay zone, When reaching the balance point, system will be freedom movement. Theory analysis and simulation outcome all prove that control arithmetic is right.4. This chapter studys the variable structure control strategy of Line certain discrete time system, Line uncertain discrete tune system and lag certain discrete time system. This design of variable structure sliding mode control for discrete time system using method of approa...