This paper addresses the problem of the dynamic positioning system of surface ships in the presence of constant environmental disturbances. In this paper we propose a high-gain observer-based PD controller to estimate unmeasured velocities of a surface ship. Lyapunov stability theory is applied to prove its stability. Finally, simulation is carried out using SIMULINK and appropriate results are obtained to illustrate the effectiveness and performance of proposed controller.

A solid-state suppress grid power supply (SGPS) is developed to be applied to the 5 MW level neutral beam injection (NBI) on HL-2M Tokamak. The power supply consists of ten modules in series, with an index of 560 V/40 A. Each of the modules is composed of an isolated transformer, rectifier, filter tank, insulated gate bipolar transistor switch, gate-drive circuit, free-wheeling diode, and so forth. An embedded system STM32F103 is used for controlling and protecting the SGPS. Meanwhile, the transient output capacity of the SGPS is tested. The effect of the output voltage of the SGPS on the extracted beam current is studied. The experimental results show that there is a turning point in the relationship between the suppress voltage and the extracted beam current. When the rate of the absolute value of the suppress voltage and the gradient voltage is more than 2.5%, the efficiency of the extracted beam of the ion source can be improved. Compared with the previous types of equipment of the NBI system, the extracted beam success rate of the new SGPS increased by more than 20%. The SGPS meets the requirements of the NBI system.

Considering bending stiffness,an finite element model is proposed to overhead transmission based on Euler beam.In this model,the displacement of the unit beam is represented by assumed mode method,and derived the mass matrix and stiffness matrixof unit beam by using assumed mode method,secondly,deduced Lagrange equation using d'Alembert principle and vibration differential equation of unit beam.And then the concept of global coordinates is proposed,which is used to represent the entire transmission line system composed of several unit beam.Taking the LGJ-400/95 as the research object,the inherent characteristics of natural frequencies and mode shapes of the transmission lines and the vibration response under the loads of the different forms can be obtained by using the finite element model to analysis the vibration characteristics of the overhead transmission lines.

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