In-Circuit Switching Loss Measurement of a Three-Level T-Type Inverter with Heterogeneous Switches

Inhalt:
Precise power-loss measurement is crucial for system efficiency modeling and thermal management. Switching loss measurement of wide-bandgap semiconductors is challenging with traditional double-pulse testing due to their fast transients. Indirect methods like calorimetric or opposition-based measurements offer significant advantages. This paper presents a method for measuring switch losses in a three-level T-Type inverter with heterogeneous switches, by only measuring the DC input power. To differentiate between switch types, an upper and a lower half-bridge are connected in an H-bridge configuration via a load inductor. A DC current is modulated through the inductor with a duty-cycle overlap, leading to hard-switching of only one switch type while the other soft-switches. By altering the current direction and modulation, switching losses can be isolated from conduction losses, allowing switching loss determination for both switch types. The method is validated through simulation and experiments.