.png)
In this paper, the design of the heat sinking in the 6kV /2500kW variable frequency drive system is studied. Forced air cooling technology is applied in the drive system. Based on the calculation of power losses, the heat sinks are designed according to the relation between power losses and temperature rise. Then, the scheme of air conduit is presented, which include: front air intake, sealed wind cavity and back air outtake. The heat sink is joined into the close wind cavity separately. The experiment results show that the heat sinking is satisfied.