Research On Thermal Design Of H-bridge Power Unit Series High-voltage Converter

This paper researches the cooling problem for the interior power unit and the whole device of the H-bridge power unit series high-voltage converter.First,according to the theory of heat transfer and fluid mechanics,forced air cooling mode is selected for the H-bridge power unit series high-voltage converter though combining the practice and comparing a variety of cooling methods.Using the thermal-electronics simulation principle,this paper analyses the thermal resistance series-parallel topology for IGBT module and heatsink,which based on,the design and material-selecting principle is given.And this paper calculates the thermal resistance and flow resistance of the heatsink,and selects centrifugal fan as well as give the operating point by considering the total power and flow resistance of the whole device.Then,this paper introduces thermal simulation principle and a thermal simulation software: Icepak.In Icepak,a simplified model of the high-voltage converter is established,which is utilized for simulating the fluid motion in order to verify whether the fan selection is reasonable and to get the lowest velocity position where a power unit locates for the further temperature simulation.Based on this,in Icepak the detailed model of power unit with IGBTs and thermal power located in the lowest velocity position is established,which is utilized for temperature simulating in order to obtain the junction temperature of IGBTs and to verify whether the thermal design is reasonable.Finally,the fluid velocity on the inlets of heatsinks and on the outlets of fan and the junction temperature of IGBTs are measured within the prototype of the high-voltage converter.As a result,the operating point of fan is calculated,and the deviation of thermal calculation and thermal simulation with the measurement will be checked,in order to verify the accuracy of thermal calculation and thermal simulation.The thermal design method of H-bridge power unit series high-voltage converter is given in this paper,which lays a foundation for the further design of other power electronic decive.