Observer Based Controller for Magnetic Levitation System
This paper explains Magnetic Levitation system of a train which comprises of guidance track made with magnets. The main objective is to design a proper controller that can suspend and propelled the train on a guidance track made with magnets. To perform the desired task state space model of Magnetic Levitation system is derived. The response of the system is simulated in MATLAB. The open loop response showed that the derived model is unstable. Observer Based Controller (OBC) is designed to analyze the system in closed loop. The controller showed improved performance for different tracks. Different types of realization techniques (minimal realization, balanced realization, modal realization, observer canonical realization) are compared for minimum fragility in controller implementation. The difference among the different realization controllers has been analyzed in detail for rounding off error or truncation error and an optimal non fragile controller design has been presented. Different disturbances were imposed upon the simulated model. All the results are analyzed in open and closed loops. The closed loop response showed that the vehicle is suspend and propelled on the track and the desired results were achieved successfully.
Discrete Time Sliding Mode Control of Magnetic Levitation System with Enhanced Exponential Reaching Law
In this study, the control of magnetic levitation system in discrete time domain is considered. Magnetic ball levitation system model is identified, linearized near the equilibrium point and discretized in convenient sampling period. Discrete time sliding mode controller with enhanced exponential reaching law is designed and compared to traditional discrete time constant proportional rate reaching law for the magnetic ball levitation system which is subject to many control problems since it has unstable structure and it has nonlinear dynamics. The asymptotically stability of the system is analyzed by using Lyapunov stability condition with discrete time approach. In order to evaluate the performance of the considered control technique, simulations are conducted and the results show that discrete time enhanced exponential reaching law provides better performance in terms of both reference tracking and disturbance noise rejection as compared to conventional constant proportional rate reaching law techniques.
The Breakdown Characteristics of the Silicone Oil for Electric Power Apparatus
The basic breakdown characteristics of the silicone oil as an insulating medium was studied with aim of realization of electric power apparatus which may be considered to be SF6 free and flame-retarding. As the first step, the impulse breakdown characteristics was measured with three kinds of electrodes whose electric field distributions differed. The breakdown characteristics in silicone oil was explained in relation to stressed oil volume (SOV) and the breakdown stress. At the second step the surface breakdown characteristic for impulse voltage was measured with two kinds of insulators which was set to between plane electrodes. The surface breakdown characteristic for impulse voltage was explained in relation to the ratio of the relative permittivity of oil and insulator. And on the third step, the breakdown characteristics of oil gap after interrupting small capacitive current was studied. In this experiment, the disconnecting switch to interrupt capacitive current was simulated by oil gap after interrupting impulse current, and to measure breakdown characteristics the high impulse voltage was subsequently applied. The breakdown stress in silicone oil after application of impulse current was discussed for insulation recovery characteristics.