功利用率的提高，关键点在于如何有效的对IGBT单元进行合理和有效的散热。
功率单元在使用两个FF450R17ME4模块达到66%利用率的额定工况时，IGBT输出频率50Hz，开关频率650Hz，功率因素0.9，单元输出电流为297A，单个IGBT芯片损耗为78.7W，单个Diode芯片损耗为23.4W。
参考业内针对过载方面的标准，均为每10min内可允许120% 过载，过载时间为持续1min。按1.2倍过载，单元输出电流为356.4A，单个IGBT芯片损耗为102W，单个Diode芯片损耗为28.9W。
单个IGBT和Diode的封装热阻和耐受温度
单个IGBT和Diode的封装热阻和耐受温度
图3-单个IGBT和Diode的封装热阻和耐受温度
（3）热管散热器仿真设计
散热器的材质为AL1060，翅片厚度1.2mm，齿间距2.5mm，散热器整体尺寸为330mm（L）*240mm（W）*93mm（H），热管采用直径为9mm的热管，热管和散热器通过Hi-Connector工艺进行紧配，如图4所示。
仿真模型详细建模散热器、热管及IGBT内部封装，边界条件为散热器出风口平均风速5m/s，环境温度40℃，海拔为1000m以下。
散热器仿真模型
散热器仿真模型
图4-散热器仿真模型
（4）额定稳态仿真结果
在IGBT稳态运行工况下，环境温度40℃，进风风速5m/s，IGBT芯片最高Tj=94.6℃，最高Tc=86.7℃，散热器压降197Pa。IGBT芯片结温均小于工作允许的结温Tj=150℃。
IGBT铜基板表面最高温度Tc
IGBT铜基板表面最高温度Tc
图5- IGBT铜基板表面最高温度Tc
IGBT芯片最高温度Tj
IGBT芯片最高温度Tj
图6- IGBT芯片最高温度Tj
稳态时芯片温度曲线 This process is called "top gas". Therefore, the phenomenon of "oxygen leakage" in the removal process can be effectively prevented. In the process of work, a fan should be started. There is also a solenoid valve for adding oxygen to the reservoir.
The oxygenation time set by this product is completed by the micro multi switch on the electronic board in the machine. From the second gear, from left to right, add oxygen respectively: 0.5, 0.5, 1 and 1 minute. The oxygenation time of 0.5 to 3 minutes can be determined by combined addition. The reason why the multi link toggle switch is adopted is that its adjustment is simple and suitable for users to set according to actual needs on site.
In application, the system composed of logo realizes automatic control.
When there is a power on signal, first enter the "regeneration" state. That is, the two three-way solenoid valves are not energized. The fan motor runs. Wait until the set "regeneration" time T1 ends, followed by the first top gas stage with a duration of T2. Then enter the "adsorption" stage with a duration of T3, and finally the second top gas stage with a
