Analysis Of Temperature Field Of Squirrel Cage Asynchronous Generator

In recent years, with the increase of wind power generation capacity, Power and losses of squirrel cage induction generator also increases gradually. Therefore, the temperature rise of each part in generator needs to be calculated accurately and controlled within a rational range for the normal operation of high-capacity wind power generators.Based on the Fluid mechanics and Heat transfer theory, it deduces the control equations for fluid flow inside the motor and determines initial and boundary conditions which is used in the simulation calculation of the motor. The finite volume method is applied for mesh generation in solution domain and derivation of discretization functions, which is solved in iteration until it is converged with given system parameters and the distributions of temperature field and fluid field are obtained. The finite volume method combines the merits of finite element method and finite difference method and couples the fluid field with temperature field together for a more precise result. This method overcomes the defects of finite element method which ignores the effects of cooling fluid’s velocity and temperature on solving process.The effect of different factors on temperature field in electric machine is analyzed for researching rationality of the machine’s design and ensuring the rational distribution of the motor temperature field and fluid field.The influence of temperature field and fluid field in stator and rotor is studied in cases with different rotating speed and inlet velocity and different ventilation structure including the wind road structure of stator back, the number of axial direction air holes in stator, the number of those in rotor and the number of radial direction air holes in stator. The good cooling effect of hydrogen as a coolant is also proved in calculation. By describing and discussing the whole paper,the conclusion of this paper is of reference value in optimization design of ventilation in stator and rotor for a safe operation of electric machines.