Active Thermal Cycling of Discrete Power Semiconductors for Applications with strong ΔT-Profiles

This paper presents a novel test system, which is optimized to simulate temperature mission profiles of various applications, which exhibit large temperature changes. The aim is to treat the investigated power semiconductor as a “black box” without the need for a lifetime model. A microcontroller controls the self-heating of the device under test to generate the necessary power losses. Simultaneously the microcontroller acquires measurement data of the device under test (DUT) based on a pre-defined test plan. To simulate also negative ambient temperatures the DUT is mounted on a cooling system. The test system has a high flexibility within a wide temperature range and can be used to simulate various application conditions, especially for applications with a large temperature swing. A mission profile focusing on the application of power semiconductors within solar inverters is used as a reference. Based on such a mission profile, heating current, gate voltage and chiller temperature are adjusted automatically to drive the system to all temperature conditions the DUT is expected to be exposed to during its lifetime in its target application.