Abstract：Inverter products have been developing towards higher power density and more compact structure.

To enhance the power density of inverter systems within a limited structural space，several prototypes need to be

made and a large number of experiments conducted during the research and development process. To shorten the

development cycle and reduce the number of prototypes and experiments，a thermal simulation method was

proposed for the power unit of the inverter. Through this method，the system steady-state temperature rise of each

scheme and the temperature rise of core components can be simulated during the research and development stage. It is possible to compare the advantages and disadvantages of different schemes without making prototypes or

conducting experiments. Experimental results verify that the thermal simulation method has relatively accurate

prediction of the cooling capacity of the thermal system. This method can effectively improve engineers' ability to

control system thermal characteristics during the power unit design stage，quickly compare the advantages and

disadvantages of different cooling solutions. It can also reduce the number of prototypes and experimental times，

increase the first-time design yield，and reduce research and development costs.

      Key words：high power；power unit；thermal simulation