大功率直驱风电机组变流器的功率器件热负荷分析

Power Device Thermal Load Characteristics Analysis of the High Power Direct-Driven Wind Turbine Converter

风速变化和风机的空气动力特性对风电变流器功率半导体器件热负荷特性的影响亟待研究。针对这个课题,对风电变流器在风速稳定和变化剧烈情况下的功率半导体器件结温进行了计算和研究。其中研究对象为兆瓦级直驱风力发电机组,研究中使用了非定常叶素动量理论中的空气动力模型,并从风速频谱的角度研究了功率器件的热应力。研究结果表明,风电机组较强的惯性使得半导体器件热特性稳定,但风速对功率器件损耗占比有影响,同时低频风速变化对损耗也有影响。

Considering the wind speed change and the aerodynamic behavior of the wind turbine,the influence of the thermal load characteristics of the semiconductor device on the wind power converter is urgent to be studied.Aiming at it,this paper calculated the junction temperature of the power semiconductor device under not only steady state,but also turbulent wind speed conditions.A typical MW level direct-driven wind turbine was studied with aerodynamic model described by Unsteady Blade Element Momentum Method(BEMM),and the thermal stress of power devices is investigated from the angle of the wind speed spectrum.It is concluded that because of the strong inertia of the wind turbine aerodynamics,the thermal stress of the converter is stable,and wind speed change the loss ratio of the IGBT and diode,and also influenced by the low band frequency of wind speed variations.