Chances and limits of a thermal control for a three-phase voltage source inverter in traction applications using permanent magnet synchronous or induction machines

摘要

The lifetime of power semiconductor devices strongly depends on their mission profile. The main influence limiting the lifetime are thermal cycles causing thermo-mechanical stress. Using the example of a three-phase voltage source inverter (VSI) feeding an induction (IM) or a permanent magnet synchronous machine (PMSM), this paper will present a thermal control strategy to increase the lifetime of the power semiconductors within the VSI. Especially within traction applications, the occurring operation points are very unsteady and rarely predictable. Therefore a thermal control is designed to dynamically react on changing operation points. The performance of the proposed thermal control using both machine types is proved at a real setup for load cycles similar to traction applications. By measuring the junction temperatures of the power semiconductors, a lifetime estimation is done to compare the different control strategies.