Temperature Sensitive Electrical Parameters (TSEPs) are promising for measurement of the IGBT junction temperature. Many TSEPs have been proposed in the literature and most require current sensors, and convoluted hardware and data processing, which are associated with increased complexity and cost. In this letter, a new TSEP is proposed called pre-threshold TSEP, VGE(pre-th). VGE(pre-th) requires only a voltage sensor and a counter. Besides less hardware requirement, VGE(pre-th) does not suffer from self-heating -a problem that most TSEPs encounter. This letter presents the operation of VGE(pre-th) with the help of simulation. Experimental tests on a 3.3kV, 800A IGBT were conducted to characterize VGE(pre-th). It is shown that the new TSEP proposed has a sensitivity of -2.2mV/°C.

This paper proposes a novel health sensitive parameter, called the gate-emitter prethreshold voltage VGE(pre-th), for detecting IGBT chip failures in multichip IGBT power modules. The proposed method has been applied in an IGBT gate driver and measures the VGE at a fixed time instant of the VGE transient before the threshold voltage occurs. To validate the proposed method, theoretical analysis and practical results for a 16-chip IGBT power module are presented in the paper. The results show a 500 mV average shift in the measured VGE(pre-th) for each IGBT chip failure.

Multi-chip Insulated Gate Bipolar Transistor (mIGBT) power modules (PMs) degrade over power cycling. Bond wire liftoff is one of the major failure modes. This paper presents a technique to diagnose bond wire lift-off by analyzing the on-state voltages across collector and emitter terminals and the voltages across collector and Kelvin emitter terminals. The proposed method can indicate the first lift-off out of 37 bond wires in a mIGBT. The main novelty of the proposed technique is that it can locate the chip that has bond wire lift-off(s). In addition, the temperature dependence of the proposed approach is negligible. The paper describes the proposed technique in detail and shows results and discussions based on practical tests which are carried out on two mIGBT PMs with different packages. Index Terms-Multi-chip insulated gate bipolar transistor, bond wire lift-off, fault diagnosis.

Silicon carbide devices have become increasingly popular in electric vehicles, predominantly due to their fast-switching speeds, which allow for the construction of smaller power converters. Temperature sensitive electrical parameters (TSEPs) can be used to determine the junction temperature, just like silicon-based power switches. This paper presents a new technique to estimate the junction temperature of a single-chip silicon carbide (SiC) metal–oxide–semiconductor field-effect transistor (MOSFET). During off-state operation, high-frequency chirp signals below the resonance frequency of the gate-source impedance are injected into the gate of a discrete SiC device. The gate-source voltage frequency response is captured and then processed using the fast Fourier transform. The data is then accumulated and displayed over the chirp frequency spectrum. Results show a linear relationship between the processed gate-source voltage and the junction temperature. The effectiveness of the proposed TSEPs is demonstrated in a laboratory scenario, where chirp signals are injected in a stand-alone biased discrete SiC module, and in an in-field scenario, where the TSEP concept is applied to a MOSFET operating in a DC/DC converter.

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Temperature Sensitive Electrical Parameters (TSEPs) are used to determine the chip temperature of a singlechip IGBT power module by measuring one electrical device parameter. Commonly, most TSEPs have a linear relationship between the chip temperature and the electrical parameter. Like any sensor, preferred attributes of TSEPs include good accuracy, linearity, and sensitivity. For multichip Insulated Gate Bipolar Transistors (mIGBTs) modules, these can only be achieved when all chips have the same temperature. Equal chip temperatures among different semiconductor chips can be achieved when placing mIGBTs in environmental chambers to produce a homogeneous temperature distribution (HTD). In real applications, however, mIGBTs are power cycled and are exposed to inhomogeneous temperature distribution (ITD) where temperature differences exist between chips. Consequently, measuring one electric parameter only cannot represent each chip temperature which impacts the TSEP sensitivity, linearity, and accuracy. This paper compares the performance of ten TSEPs applied to a mIGBT module operating at HTD and ITD conditions in order to determine which TSEPs are most suitable for mIGBTs in real applications.

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