Study On Geometry Optimization Of Pole Shoes, Parameter Calculation, And Transient Behavior Simulation Of Hydrogenerators With Multi-section Arc Pole Shoes

This dissertation covers the studies on the geometry optimization of pole shoes, the numerical calculation of parameters, and the digital simulation of transient performences of large hydro-generators with multi-section arc geometry of pole shoes,concerning the cruxes of the technique in design and manufacturing. It mainly consists of four parts.The global optimization algorithm for multimodal functions of both continuous and discrete variables are studied in the first part. The dissertation takes the head in implemcnting and improving the Simulated Annealing(SA) algorithm in the inverse problem of electrical machines. The most significant improvements made in this dissertation include three parts. The first one is a self-adaptive regulation schedule for the step vector, the second a dynamic terminitive criterion for Metropolis process , and the third the combined strategies of SA and Genetic algorithm as well as SA and the deterministic algorithm based on two different transition criteria.Some feasible numerical methods for the computation of static and transient parameters based on the numerical solutions of 2D static magnetic field, the 2D transient eddy cutrent field, and 3D end region magnetic field are given in the second part. The parameter charts commonly used in the electromagnetic design and those of equivalent d- and q- axis open circuit characteristics used in digital simulations are also calculated in the dissertation.The mathematical model of the geometry optimization for pole shoes is evaluated in the third part. Some special problems of inverse problems are also investigated. Then a software is developed, and the optimal geometry and size of pole shoes are discussed through numerical results of different hydro-generators.Two type of mathematical models, one from the circuit phase and the other from the transient eddy current field phase, are derived in the fourth part, for simulating the transient behaviors of large hydro( turbine)-generators. The studies focus on the consideration of speed variation and its effects on parameters, the saturation effects of iron materials, the approach to treat faults and switching operations as well as the common method to coupled different models in circuit phase, and the measure to surpress the numerical oscillation in the eddy current field phase. On the workjust mentioned above, an electromagnetic transient program is built up, and the transient behaviors of large hydro-generator with multi-section arc pole shoes under different electrical fault and switching operation are discussed thoroughly. Some of the numerical results in this dissertation are first published so far.