功率器件散热特性的非稳态测量方法

摘要

The heat dissipation system of power electronic device is analyzed based upon a lumped method.The temperature-changing rules during unsteady-state heat conduction are deduced and therefore a method is proposed for charactering system heat dissipation properties by measurement of temperature-changing curves during unsteady-state heat conduction process.Taking the power module as an example,the temperature increasing and decreasing processes are experimentally measured under different conditions.The measurement results agree well with the theoretical prediction,indicating that such a method can be effectively applied in practical engineering applications.The proposed method can not only avoid the complicated computations,but also provide a convenient way for obtaining the heat dissipation properties of power electronic devices and predicting the maximum temperature rise.It is especially applicable to those application cases that the heat dissipation structures are complicated and the heat boundary conditions are difficult to be confirmed.%采用集总参数法对功率器件的散热体系进行了分析,推导了功率器件非稳态导热过程中温度变化的规律,给出了一种通过测量非稳态导热过程中的温度变化曲线确定散热体系特性参数的方法。以模块电源为例,实际测量了在不同状态下电源模块升温及降温过程中的温度变化特性。测试结果与理论预测基本相符,表明这种方法可有效用于工程实际中。该方法不仅可以避免冗繁的计算,且通过实验可方便地测试出功率器件的散热特性,并能够预测其使用过程中的最大温升,尤其适用于散热结构复杂、散热边界条件不易确定的应用场合。