兆瓦级永磁同步发电机温升的数值计算研究

针对兆瓦级永磁同步发电机设计中采用温度敏感性永磁材料的温升控制,基于等效热路法和温度场法,根据永磁同步发电机的等效热路图计算了其内部温升。重点研究了以电机内温升为边界条件的定子端面温度场的数学模型,采用有限差分法求解温度场模型,得到了电机定子端面的热导矩阵;通过Jacobi迭代,得到电机内冷却空气进、出口处的定子端面温度场。数值计算的结果表明,冷却空气出口处定子端面温度场的温度梯度明显高于冷却空气的入口端,其温度极值低于牌号N42SH的钕铁硼永磁材料最高工作温度,定子内绕组最高温升亦低于F级绝缘电机的温升限值。研究结果对兆瓦级永磁同步发电机的设计、样机试验提供了理论依据。

Research on Temperature Rising Numerical Calculation for Megawatt Level Permanent Magnetism Synchronous Generator

Based on equivalent thermal circuit method and temperature-field method,the temperature rising had been calculated with its equivalent thermal circuit diagram for temperature rising control on temperature-sensitive permanent magnetic material in permanent magnetism synchronous generator in this paper.The research focuses on mathematic model of stator side face with the temperature rising boundary conditions in permanent magnetism synchronous generator.Based on finite difference method the thermal conductivity matrix has been got.Through the Jacobi iteration,temperature-fields of two stator side faces have been calculated.The numerical results show that the temperature grads of stator side face in the cooling air exit were much higher than those of stator side face in the cooling air inlet,whose maximum temperature in stator was lower than maximum work temperature of designation N42SH Nd-Fe-B permanent magnetic material with temperature rising of coils in stator also lower than F lever generator＇s temperature limit.The results of study provide theoretical foundation for designing and prototyping test of permanent magnetism synchronous generator.