Kevin Muñoz Barón

Zusammenfassung

A measurement setup for health and wear-out monitoring via electrical parameters is implemented in a test bench to allow online parameter observation during inverter operation for silicon carbide MOSFETs. A variety of electrical parameters are known to change during operation and over the lifetime of power semiconductor devices and can be an indicator of impending end of life. The observed parameters in this work are drain-source voltage as an indicator of bond-wire fatigue, gate current, indicating degradation in the gate oxide and threshold voltage, which is known to drift in silicon carbide power devices. Due to the isolated measurement design, high-side acquisition of electrical parameters is possible as well. Measurements in a buck-converter configuration are carried out, showing high stability in the output of the implemented acquisition circuits with an update rate of 200 samples per second. This approach has a strong significance in the development of novel power cycling test stands which combine switching losses with conduction losses.

Zusammenfassung

This paper presents a robust and easy-to-implement approach to measure the junction temperature of SiC power devices using quasi-threshold voltage as temperature sensitive electrical parameter with adjustable temperature sensitivity. The voltage drop across the parasitic inductance between Kelvin and power source is used to trigger the data acquisition circuit. The novelty of the proposed method lies in the concept of variable temperature sensitivity where the robustness decreases with the increase in the sensitivity. This concept proposes a trade-off between temperature sensitivity and robustness. A D flip-flop is used to make the acquisition circuit more robust to prevent false triggering while keeping fast switching speed and low noise susceptibility. Basic simulations, static and dynamic measurements are performed successfully on a commercially available 1.2 kV/120 A power module in a buck converter topology. The effect of DC-link voltage and load current invariance is also verified in this paper.

Zusammenfassung

This paper presents a robust and easy-to-implement approach to measure junction temperature of SiC power devices using quasi-threshold voltage as temperature sensitive electrical parameter with adjustable temperature sensitivity. Static and dynamic measurements were performed and compared on a commercially available 1.2 kV/120 A SiC power module. The voltage drop across the parasitic inductor is used as the trigger for the data acquisition circuit. A robust approach by using a D-flip-flop for latching in data acquisition circuit while keeping fast turn-on behavior and low noise susceptibility in consideration with the option of variable sensitivity has been successfully implemented and presented.

Zusammenfassung

In many power electronic applications, it is important to monitor the junction temperature of the power semiconductor devices. This enables for example an abnormal temperature protection, lifetime monitoring or junction temperature control. This paper proposes an online junction temperature measurement based on the internal gate resistance as a temperature sensitive electrical parameter. A direct measurement of this resistance is not possible. Therefore, a high frequency signal is injected into the gate circuit to measure the gate circuit's impedance, which includes the temperature sensitive internal gate resistance. This paper focuses on a simple realization of this method.